/Client/MicrosoftAjax/Extensions/Sys/WebForms/PageRequestManager.js

$type = Sys.WebForms.PageRequestManager = function PageRequestManager() {

    this._form = null;

    this._activeDefaultButton = null;

    this._activeDefaultButtonClicked = false;

    this._updatePanelIDs = null;

    this._updatePanelClientIDs = null;

    this._updatePanelHasChildrenAsTriggers = null;

    this._asyncPostBackControlIDs = null;

    this._asyncPostBackControlClientIDs = null;

    this._postBackControlIDs = null;

    this._postBackControlClientIDs = null;

    this._scriptManagerID = null;

    this._pageLoadedHandler = null;



    this._additionalInput = null;

    this._onsubmit = null;

    this._onSubmitStatements = [];

    this._originalDoPostBack = null;

    this._originalDoPostBackWithOptions = null;

    this._originalFireDefaultButton = null;

    this._originalDoCallback = null;

    this._isCrossPost = false;

    this._postBackSettings = null;

    this._request = null;

    this._onFormSubmitHandler = null;

    this._onFormElementClickHandler = null;

    this._onWindowUnloadHandler = null;

    this._asyncPostBackTimeout = null;



    this._controlIDToFocus = null;

    this._scrollPosition = null;

    this._processingRequest = false;

    this._scriptDisposes = {};

    

    // DevDiv Bugs 161922, 138251:

    // List of hidden fields that should be removed if an async update does not

    // explictly define it.

    this._transientFields = ["__VIEWSTATEENCRYPTED", "__VIEWSTATEFIELDCOUNT"];

}



$type.prototype = {

    get_isInAsyncPostBack: function PageRequestManager$get_isInAsyncPostBack() {

        /// <value type="Boolean" locid="P:J#Sys.WebForms.PageRequestManager.isInAsyncPostBack"></value>

        //#if DEBUG

        if (arguments.length !== 0) throw Error.parameterCount();

        //#endif

        return this._request !== null;

    },



    // Events

    add_beginRequest: function PageRequestManager$add_beginRequest(handler) {

        /// <summary locid="E:J#Sys.WebForms.PageRequestManager.beginRequest">Adds a beginRequest event handler.</summary>

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.addEventHandler(this, "beginRequest", handler);

    },

    remove_beginRequest: function PageRequestManager$remove_beginRequest(handler) {

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.removeEventHandler(this, "beginRequest", handler);

    },



    add_endRequest: function PageRequestManager$add_endRequest(handler) {

        /// <summary locid="E:J#Sys.WebForms.PageRequestManager.endRequest">Adds a endRequest event handler.</summary>

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.addEventHandler(this, "endRequest", handler);

    },

    remove_endRequest: function PageRequestManager$remove_endRequest(handler) {

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.removeEventHandler(this, "endRequest", handler);

    },



    add_initializeRequest: function PageRequestManager$add_initializeRequest(handler) {

        /// <summary locid="E:J#Sys.WebForms.PageRequestManager.initializeRequest">Adds a initializeRequest event handler.</summary>

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.addEventHandler(this, "initializeRequest", handler);

    },

    remove_initializeRequest: function PageRequestManager$remove_initializeRequest(handler) {

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.removeEventHandler(this, "initializeRequest", handler);

    },



    add_pageLoaded: function PageRequestManager$add_pageLoaded(handler) {

        /// <summary locid="E:J#Sys.WebForms.PageRequestManager.pageLoaded">Adds a pageLoaded event handler.</summary>

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.addEventHandler(this, "pageLoaded", handler);

    },

    remove_pageLoaded: function PageRequestManager$remove_pageLoaded(handler) {

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.removeEventHandler(this, "pageLoaded", handler);

    },



    add_pageLoading: function PageRequestManager$add_pageLoading(handler) {

        /// <summary locid="E:J#Sys.WebForms.PageRequestManager.pageLoading">Adds a pageLoading event handler.</summary>

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.addEventHandler(this, "pageLoading", handler);

    },

    remove_pageLoading: function PageRequestManager$remove_pageLoading(handler) {

        //#if DEBUG

        var e = Function._validateParams(arguments, [{name: "handler", type: Function}]);

        if (e) throw e;

        //#endif

        Sys.Observer.removeEventHandler(this, "pageLoading", handler);

    },



    abortPostBack: function PageRequestManager$abortPostBack() {

        if (!this._processingRequest && this._request) {

            // cancel the request if a response hasn't already been received

            this._request.get_executor().abort();

            this._request = null;

        }

    },



    beginAsyncPostBack: function PageRequestManager$beginAsyncPostBack(updatePanelsToUpdate, eventTarget, eventArgument, causesValidation, validationGroup) {

        /// <summary locid="M:J#Sys.WebForms.PageRequestManager.beginAsyncPostBack">Begins an asynchronous postback.</summary>

        /// <param name="updatePanelsToUpdate" type="Array" elementType="String" mayBeNull="true" optional="true">A list of UniqueIDs or ClientIDs of UpdatePanel controls that should have their rendering updated.</param>

        /// <param name="eventTarget" type="String" mayBeNull="true" optional="true"></param>

        /// <param name="eventArgument" type="String" mayBeNull="true" optional="true"></param>

        /// <param name="causesValidation" type="Boolean" mayBeNull="true" optional="true"></param>

        /// <param name="validationGroup" type="String" mayBeNull="true" optional="true"></param>

        //#if DEBUG

        var e = Function._validateParams(arguments, [

            {name: "updatePanelsToUpdate", type: Array, mayBeNull: true, optional: true, elementType: String},

            {name: "eventTarget", type: String, mayBeNull: true, optional: true},

            {name: "eventArgument", type: String, mayBeNull: true, optional: true},

            {name: "causesValidation", type: Boolean, mayBeNull: true, optional: true},

            {name: "validationGroup", type: String, mayBeNull: true, optional: true}

        ]);

        if (e) throw e;

        //#endif

        if (causesValidation && (typeof(Page_ClientValidate) === 'function') && !Page_ClientValidate(validationGroup || null)) {

            return;

        }

        this._postBackSettings = this._createPostBackSettings(true, updatePanelsToUpdate, eventTarget);

        var form = this._form;

        form.__EVENTTARGET.value = (eventTarget || "");

        form.__EVENTARGUMENT.value = (eventArgument || "");

        this._isCrossPost = false;

        this._additionalInput = null;

        this._onFormSubmit();

    },

    

    _cancelPendingCallbacks: function PageRequestManager$_cancelPendingCallbacks() {

        // DevDiv Bugs 125825: To avoid EVENTVALIDATION corruption we must cancel pending callbacks when an async postback begins

        // to cancel callbacks, we run logic similar to WebForm_CallbackComplete,

        // except we do not run WebForm_ExecuteCallback for them. This code is exactly

        // WebForm_CallbackComplete except without the call to WebForm_ExecuteCallback.

        // We are basically treating each callback as completed, ignoring the response if any.

        for (var i = 0, l = window.__pendingCallbacks.length; i < l; i++) {

            var callback = window.__pendingCallbacks[i];

            if (callback) {

                if (!callback.async) {

                    // we just cancelled the single allowed instance of a synchronous callback

                    window.__synchronousCallBackIndex = -1;

                }

                window.__pendingCallbacks[i] = null;

                var callbackFrameID = "__CALLBACKFRAME" + i;

                var xmlRequestFrame = document.getElementById(callbackFrameID);

                if (xmlRequestFrame) {

                    xmlRequestFrame.parentNode.removeChild(xmlRequestFrame);

                }

            }

        }

    },

    

    _commitControls: function PageRequestManager$_commitControls(updatePanelData, asyncPostBackTimeout) {

        // DevDiv Bugs 154403:

        // commits context data parsed from a delta. This is called after an async response

        // has proceeded past the script include loading phase, which when it can no longer

        // be cancelled and the HTML DOM will be updated.

        // _processUpdatePanelArrays is the method that creates these arrays..

        // DevDiv Bugs 188564: Update may not have an async postback timeout node and/or updatepanel nodes.

        if (updatePanelData) {

            this._updatePanelIDs = updatePanelData.updatePanelIDs;

            this._updatePanelClientIDs = updatePanelData.updatePanelClientIDs;

            this._updatePanelHasChildrenAsTriggers = updatePanelData.updatePanelHasChildrenAsTriggers;

            this._asyncPostBackControlIDs = updatePanelData.asyncPostBackControlIDs;

            this._asyncPostBackControlClientIDs = updatePanelData.asyncPostBackControlClientIDs;

            this._postBackControlIDs = updatePanelData.postBackControlIDs;

            this._postBackControlClientIDs = updatePanelData.postBackControlClientIDs;

        }

        if (typeof(asyncPostBackTimeout) !== 'undefined' && asyncPostBackTimeout !== null) {

            this._asyncPostBackTimeout = asyncPostBackTimeout * 1000;

        }

    },

    

    _createHiddenField: function PageRequestManager$_createHiddenField(id, value) {

        // DevDiv Bugs 27075: Creates a hidden field via innerHTML to workaround a caching issue.

        var container, field = document.getElementById(id);



        if (field) {

            // the field already exists

            if (!field._isContained) {

                // but it is not contained within a SPAN container, so we must create one

                // in order to recreate it with innerHTML.

                field.parentNode.removeChild(field);

            }

            else {

                // and it already has a container, we'll just set the container innerHTML to replace it,

                // which is much faster than removing the element, recreating it, and then setting innerHTML

                container = field.parentNode;

            }

        }

        if (!container) {

            container = document.createElement('span');

            // set display none in case this SPAN would be styled

            container.style.cssText = "display:none !important";

            this._form.appendChild(container);

        }

        // now create/replace the input by setting innerHTML

        container.innerHTML = "<input type='hidden' />";

        field = container.childNodes[0];

        // flag it as contained, so if it needs to be removed we know to remove the container, too.

        field._isContained = true;

        field.id = field.name = id;

        field.value = value;

    },



    _createPageRequestManagerTimeoutError: function PageRequestManager$_createPageRequestManagerTimeoutError() {

        // Creates a PageRequestManagerTimeoutException representing a request that timed out.

        var displayMessage = "Sys.WebForms.PageRequestManagerTimeoutException: " + Sys.WebForms.Res.PRM_TimeoutError;

        var e = Error.create(displayMessage, {name: 'Sys.WebForms.PageRequestManagerTimeoutException'});

        e.popStackFrame();

        return e;

    },



    _createPageRequestManagerServerError: function PageRequestManager$_createPageRequestManagerServerError(httpStatusCode, message) {

        // Creates a PageRequestManagerServerErrorException representing an error that occurred on the server.

        var displayMessage = "Sys.WebForms.PageRequestManagerServerErrorException: " +

            (message || String.format(Sys.WebForms.Res.PRM_ServerError, httpStatusCode));

        var e = Error.create(displayMessage, {

            name: 'Sys.WebForms.PageRequestManagerServerErrorException',

            httpStatusCode: httpStatusCode

        });

        e.popStackFrame();

        return e;

    },



    _createPageRequestManagerParserError: function PageRequestManager$_createPageRequestManagerParserError(parserErrorMessage) {

        // Creates a PageRequestManagerParserErrorException representing a parser error that occurred while processing a response from the server.

        var displayMessage = "Sys.WebForms.PageRequestManagerParserErrorException: " + String.format(Sys.WebForms.Res.PRM_ParserError, parserErrorMessage);

        var e = Error.create(displayMessage, {name: 'Sys.WebForms.PageRequestManagerParserErrorException'});

        e.popStackFrame();

        return e;

    },



    _createPanelID: function PageRequestManager$_createPanelID(panelsToUpdate, postBackSettings) {

        var asyncTarget = postBackSettings.asyncTarget,

            toUpdate = this._ensureUniqueIds(panelsToUpdate || postBackSettings.panelsToUpdate),

            panelArg = (toUpdate instanceof Array)

                ? toUpdate.join(',')

                : (toUpdate || this._scriptManagerID);

        if (asyncTarget) {

            panelArg += "|" + asyncTarget;

        }

        return encodeURIComponent(this._scriptManagerID) + '=' + encodeURIComponent(panelArg) + '&';

    },



    _createPostBackSettings: function PageRequestManager$_createPostBackSettings(async, panelsToUpdate, asyncTarget, sourceElement) {

        return { async:async, asyncTarget: asyncTarget, panelsToUpdate: panelsToUpdate, sourceElement: sourceElement };

    },



    _convertToClientIDs: function PageRequestManager$_convertToClientIDs(source, destinationIDs, destinationClientIDs, version4) {

        if (source) {

            for (var i = 0, l = source.length; i < l; i += (version4 ? 2 : 1)) {

                var uniqueID = source[i],

                    clientID = (version4 ? source[i+1] : "") || this._uniqueIDToClientID(uniqueID);

                Array.add(destinationIDs, uniqueID);

                Array.add(destinationClientIDs, clientID);

            }

        }

    },



    dispose: function PageRequestManager$dispose() {

        Sys.Observer.clearEventHandlers(this);

        if (this._form) {

            Sys.UI.DomEvent.removeHandler(this._form, 'submit', this._onFormSubmitHandler);

            Sys.UI.DomEvent.removeHandler(this._form, 'click', this._onFormElementClickHandler);

            Sys.UI.DomEvent.removeHandler(window, 'unload', this._onWindowUnloadHandler);

            Sys.UI.DomEvent.removeHandler(window, 'load', this._pageLoadedHandler);

        }



        if (this._originalDoPostBack) {

            window.__doPostBack = this._originalDoPostBack;

            this._originalDoPostBack = null;

        }

        if (this._originalDoPostBackWithOptions) {

            window.WebForm_DoPostBackWithOptions = this._originalDoPostBackWithOptions;

            this._originalDoPostBackWithOptions = null;

        }

        if (this._originalFireDefaultButton) {

            window.WebForm_FireDefaultButton = this._originalFireDefaultButton;

            this._originalFireDefaultButton = null;

        }

        if (this._originalDoCallback) {

            window.WebForm_DoCallback = this._originalDoCallback;

            this._originalDoCallback = null;

        }



        this._form = null;

        this._updatePanelIDs = null;

        this._updatePanelClientIDs = null;

        this._asyncPostBackControlIDs = null;

        this._asyncPostBackControlClientIDs = null;

        this._postBackControlIDs = null;

        this._postBackControlClientIDs = null;

        this._asyncPostBackTimeout = null;

        this._scrollPosition = null;

    },

    

    _doCallback: function PageRequestManager$_doCallback(eventTarget, eventArgument, eventCallback, context, errorCallback, useAsync) {

        // DevDiv Bugs 125825: Do not allow callbacks to begin while an async postback is in progress to prevent EVENTVALIDATION corruption

        if (!this.get_isInAsyncPostBack()) {

            this._originalDoCallback(eventTarget, eventArgument, eventCallback, context, errorCallback, useAsync);

        }

    },



    // New implementation of __doPostBack

    _doPostBack: function PageRequestManager$_doPostBack(eventTarget, eventArgument) {

        this._additionalInput = null;



        var form = this._form;

        if ((eventTarget === null) || (typeof(eventTarget) === "undefined") || (this._isCrossPost)) {

            // Allow the default form submit to take place. Since it's a cross-page postback.

            // DevDiv 80942: we should fall to a full postback if event target is null or undefined

            this._postBackSettings = this._createPostBackSettings(false);

            // set to false so subsequent posts that don't go through DPWO aren't considered cross post

            this._isCrossPost = false;

        }

        else {

            var mpUniqueID = this._masterPageUniqueID;

            // If it's not a cross-page post, see if we can find the DOM element that caused the postback

            var clientID = this._uniqueIDToClientID(eventTarget);

            var postBackElement = document.getElementById(clientID);

            if (!postBackElement && mpUniqueID) {

                if (clientID.indexOf(mpUniqueID + "$") === 0) {

                    // With ClientIDMode=Predictable, the MasterPageID is missing from the beginning

                    // of the client ID.

                    postBackElement = document.getElementById(clientID.substr(mpUniqueID.length + 1));

                }

            }

            if (!postBackElement) {

                // If the control has no matching DOM element we look for an exact

                // match from RegisterAsyncPostBackControl or RegisterPostBackControl.

                // If we can't find anything about it then we do a search based on

                // naming containers to still try and find a match.

                if (Array.contains(this._asyncPostBackControlIDs, eventTarget)) {

                    // Exact match for async postback

                    this._postBackSettings = this._createPostBackSettings(true, null, eventTarget);

                }

                else {

                    if (Array.contains(this._postBackControlIDs, eventTarget)) {

                        // Exact match for regular postback

                        this._postBackSettings = this._createPostBackSettings(false);

                    }

                    else {

                        // Find nearest element based on UniqueID in case the element calling

                        // __doPostBack doesn't have an ID. GridView does this for its Update

                        // button and without this we can't do async postbacks.

                        var nearestUniqueIDMatch = this._findNearestElement(eventTarget);

                        if (nearestUniqueIDMatch) {

                            // We found a related parent element, so walk up the DOM to find out what kind

                            // of postback we should do.

                            this._postBackSettings = this._getPostBackSettings(nearestUniqueIDMatch, eventTarget);

                        }

                        else {

                            // the control may have rendered without the master page id prefix due to ClientIDMode = Predictable

                            // For example "ctl00$ctl00$foo$Button1" may have rendered an id of "foo_button1" if "ctl00$ctl00" 

                            // is the ID for a 2-level nested master page.

                            // try stripping it from the beginning of the ID and trying again

                            if (mpUniqueID) {

                                mpUniqueID += "$";

                                if (eventTarget.indexOf(mpUniqueID) === 0) {

                                    nearestUniqueIDMatch = this._findNearestElement(eventTarget.substr(mpUniqueID.length));

                                }

                            }

                            if (nearestUniqueIDMatch) {

                                // We found a related parent element, so walk up the DOM to find out what kind

                                // of postback we should do.

                                this._postBackSettings = this._getPostBackSettings(nearestUniqueIDMatch, eventTarget);

                            }

                            else {

                                // Can't find any DOM element at all related to the eventTarget,

                                // so we just give up and do a regular postback.

                                this._postBackSettings = this._createPostBackSettings(false);

                            }

                        }

                    }

                }

            }

            else {

                // The element was found, so walk up the DOM to find out what kind

                // of postback we should do.

                this._postBackSettings = this._getPostBackSettings(postBackElement, eventTarget);

            }

        }



        if (!this._postBackSettings.async) {

            // Temporarily restore the form's onsubmit handler expando while calling

            // the original ASP.NET 2.0 __doPostBack() function.

            form.onsubmit = this._onsubmit;

            this._originalDoPostBack(eventTarget, eventArgument);

            form.onsubmit = null;

            return;

        }



        form.__EVENTTARGET.value = eventTarget;

        form.__EVENTARGUMENT.value = eventArgument;

        this._onFormSubmit();

    },



    _doPostBackWithOptions: function PageRequestManager$_doPostBackWithOptions(options) {

        this._isCrossPost = options && options.actionUrl;

        // note that when DoPostBackWithOptions is used, _doPostBack or _onFormSubmit, one of the two,

        // are guaranteed to be called next.

        // In both of those methods it is important to clear the isCrossPost flag so subsequent posts that

        // don't use DoPostBackWithOptions are not considered cross page posts.

        this._originalDoPostBackWithOptions(options);

    },



    _elementContains: function PageRequestManager$_elementContains(container, element) {

        while (element) {

            if (element === container) {

                return true;

            }

            element = element.parentNode;

        }

        return false;

    },



    _endPostBack: function PageRequestManager$_endPostBack(error, executor, data) {

        if (this._request === executor.get_webRequest()) {

            // the postback being ended is the one being processed

            this._processingRequest = false;

            this._additionalInput = null;

            this._request = null;

        }



        var eventArgs = new Sys.WebForms.EndRequestEventArgs(error, data ? data.dataItems : {}, executor);

        Sys.Observer.raiseEvent(this, "endRequest", eventArgs);

        if (error && !eventArgs.get_errorHandled()) {

            // DevDiv 89485: throw, don't alert()

            throw error;

        }

    },



    _ensureUniqueIds: function PageRequestManager$_ensureUniqueIds(ids) {

        // given a single ID or an array of IDs that might be ClientIDs or UniqueIDs,

        // returns a list of the UniqueIDs. This is used from createPanelID and makes

        // it so beginAsyncPostBack and the panelstoUpdate property of the event args

        // supports a list of update panels by UniqueID or ClientID.

        // If an ID is not a ClientID we assume it is a UniqueID even though it could just be

        // that it does not exist.

        if (!ids) return ids;

        ids = ids instanceof Array ? ids : [ids];

        var uniqueIds = [];

        for (var i = 0, l = ids.length; i < l; i++) {

            var id = ids[i], index = Array.indexOf(this._updatePanelClientIDs, id);

            uniqueIds.push(index > -1 ? this._updatePanelIDs[index] : id);

        }

        return uniqueIds;

    },



    // Finds the nearest element to the given UniqueID. If an element is not

    // found for the exact UniqueID, it walks up the parent chain to look for it.

    _findNearestElement: function PageRequestManager$_findNearestElement(uniqueID) {

        while (uniqueID.length > 0) {

            var clientID = this._uniqueIDToClientID(uniqueID);

            var element = document.getElementById(clientID);

            if (element) {

                return element;

            }

            var indexOfLastDollar = uniqueID.lastIndexOf('$');

            if (indexOfLastDollar === -1) {

                return null;

            }

            uniqueID = uniqueID.substring(0, indexOfLastDollar);

        }

        return null;

    },



    _findText: function PageRequestManager$_findText(text, location) {

        var startIndex = Math.max(0, location - 20);

        var endIndex = Math.min(text.length, location + 20);

        return text.substring(startIndex, endIndex);

    },

    

    _fireDefaultButton: function PageRequestManager$_fireDefaultButton(event, target) {

        // This is a copy of the function WebForm_FireDefaultButton as defined in WebForms.js.

        // The purpose is to hook into the WebForm_FireDefaultButton call with the code commented in the middle.

        // Other than that, there have been a few minor changes to the code but the logic is the same.

        if (event.keyCode === 13) {

            var src = event.srcElement || event.target;

            if (!src || (src.tagName.toLowerCase() !== "textarea")) {

                var defaultButton = document.getElementById(target);



                if (defaultButton && (typeof(defaultButton.click) !== "undefined")) {

                    

                    // Beginning of new code...

                    

                    // In all but FF this causes the form.onclick event to fire with the button as the event target.

                    // In FF the the form.onclick event has the current focus control as the target, which prevents the

                    // default button's server-side click event from firing. So we ensure the correct control is determined

                    // to have caused the postback by saving the default button before clicking on it. The code in

                    // onFormSubmit looks for this field and ensures the postback target is the button.

                    this._activeDefaultButton = defaultButton;

                    this._activeDefaultButtonClicked = false;

                    try {

                        // click is synchronous -- it will immediately cause a form onclick event and then a form onsubmit event

                        // assuming nothing uses preventDefault() to cancel the event.

                        defaultButton.click();

                    }

                    finally {

                        // form submission may or may not be occuring after this point

                        this._activeDefaultButton = null;

                    }

                    

                    // ...End of new code

                    

                    // cancel submission caused by hitting enter in the input control

                    event.cancelBubble = true;

                    if (typeof(event.stopPropagation) === "function") {

                        event.stopPropagation();

                    }

                    return false;

                }

            }

        }

        return true;

    },



    _getPageLoadedEventArgs: function PageRequestManager$_getPageLoadedEventArgs(initialLoad, data) {

        // -------------+------------------------------------+-----------------------

        // Situation    | In ID collections                  | In eventArg property

        // -------------+------------------------------------+-----------------------

        // Update (exp) | in panelsToRefresh                 | updated

        // Update (imp) | in new, in old, in childUP         | created

        // Create (exp) | in new, not in old, not in childUP | created

        // Create (imp) | in new, not in old, in childUP     | created

        // Delete (exp) | not in new, in old, not in childUP | ---

        // Delete (imp) | not in new, in old, in childUP     | ---

        // -------------+------------------------------------+-----------------------

        // (exp) = explicit

        // (imp) = implicit (happened as result of parent UpdatePanel updating)

        // --------------------------------------------------------------------------

        // in panelsToRefresh = updated

        // not updated, in new = created

        // else = don't care

        // --------------------------------------------------------------------------



        var updated = [];

        var created = [];

        var version4 = data ? data.version4 : false;

        var upData = data ? data.updatePanelData : null;



        // All panels before update,

        // All panels after update,

        // Child panels created after update,

        // Parent panels created after update

        var newIDs, newClientIDs, childIDs, refreshedIDs;



        if (!upData) {

            // this is the initial load, consider the initialized update panels

            // to be the newly created ones

            newIDs = this._updatePanelIDs;

            newClientIDs = this._updatePanelClientIDs;

            childIDs = null;

            refreshedIDs = null;

        }

        else {

            newIDs = upData.updatePanelIDs;

            newClientIDs = upData.updatePanelClientIDs;

            childIDs = upData.childUpdatePanelIDs;

            refreshedIDs = upData.panelsToRefreshIDs;

        }



        var i, l, uniqueID, clientID;

        // in panelsToRefresh = updated

        if (refreshedIDs) {

            for (i = 0, l = refreshedIDs.length; i < l; i += (version4 ? 2 : 1)) {

                uniqueID = refreshedIDs[i];

                clientID = (version4 ? refreshedIDs[i+1] : "") || this._uniqueIDToClientID(uniqueID);

                Array.add(updated, document.getElementById(clientID));

            }

        }



        // If the panel is in the new list and it is either the initial load

        // of the page a refreshed child, it is 'created'.

        for (i = 0, l = newIDs.length; i < l; i++) {

            if (initialLoad || Array.indexOf(childIDs, newIDs[i]) !== -1) {

                Array.add(created, document.getElementById(newClientIDs[i]));

            }

        }



        return new Sys.WebForms.PageLoadedEventArgs(updated, created, data ? data.dataItems : {});

    },



    _getPageLoadingEventArgs: function PageRequestManager$_getPageLoadingEventArgs(data) {

        // -------------+------------------------------------+-----------------------

        // Situation    | In ID collections                  | In eventArg property

        // -------------+------------------------------------+-----------------------

        // Update (exp) | in panelsToRefresh                 | updated

        // Update (imp) | in old, in new, in childUP         | deleted

        // Create (exp) | not in old, in new, not in childUP | ---

        // Create (imp) | not in old, in new, in childUP     | ---

        // Delete (exp) | in old, not in new, not in childUP | deleted

        // Delete (imp) | in old, not in new, in childUP     | deleted

        // -------------+------------------------------------+-----------------------

        // (exp) = explicit

        // (imp) = implicit (happened as result of parent UpdatePanel updating)

        // --------------------------------------------------------------------------

        // in panelsToRefresh = updated

        // not updated, (not in new or in childUP) = deleted

        // else = don't care

        // --------------------------------------------------------------------------



        var updated = [],

            deleted = [],

            upData = data.updatePanelData,

            oldIDs = upData.oldUpdatePanelIDs,

            oldClientIDs = upData.oldUpdatePanelClientIDs,

            newIDs = upData.updatePanelIDs,

            childIDs = upData.childUpdatePanelIDs,

            refreshedIDs = upData.panelsToRefreshIDs,

            i, l, uniqueID, clientID,

            version4 = data.version4;

        // in panelsToRefresh = updated

        for (i = 0, l = refreshedIDs.length; i < l; i += (version4 ? 2 : 1)) {

            uniqueID = refreshedIDs[i];

            clientID = (version4 ? refreshedIDs[i+1] : "") || this._uniqueIDToClientID(uniqueID);

            Array.add(updated, document.getElementById(clientID));

        }



        // not in new or in childUP = deleted

        for (i = 0, l = oldIDs.length; i < l; i++) {

            uniqueID = oldIDs[i];

            if (Array.indexOf(refreshedIDs, uniqueID) === -1 &&

                (Array.indexOf(newIDs, uniqueID) === -1 || Array.indexOf(childIDs, uniqueID) > -1)) {

                Array.add(deleted, document.getElementById(oldClientIDs[i]));

            }

        }



        return new Sys.WebForms.PageLoadingEventArgs(updated, deleted, data.dataItems);

    },



    _getPostBackSettings: function PageRequestManager$_getPostBackSettings(element, elementUniqueID) {



        var originalElement = element;



        // Keep track of whether we have an AsyncPostBackControl but still

        // want to see if we're inside an UpdatePanel anyway.

        var proposedSettings = null;



        // Walk up DOM hierarchy to find out the nearest container of

        // the element that caused the postback.

        while (element) {

            if (element.id) {

                // First try an exact match for async postback, regular postback, or UpdatePanel

                if (!proposedSettings && Array.contains(this._asyncPostBackControlClientIDs, element.id)) {

                    // The element explicitly causes an async postback

                    proposedSettings = this._createPostBackSettings(true, null, elementUniqueID, originalElement);

                }

                else {

                    if (!proposedSettings && Array.contains(this._postBackControlClientIDs, element.id)) {

                        // The element explicitly doesn't cause an async postback

                        return this._createPostBackSettings(false);

                    }

                    else {

                        var indexOfPanel = Array.indexOf(this._updatePanelClientIDs, element.id);

                        if (indexOfPanel !== -1) {

                            // The element causes an async postback because it is inside an UpdatePanel

                            if (this._updatePanelHasChildrenAsTriggers[indexOfPanel]) {

                                // If it was in an UpdatePanel and the panel has ChildrenAsTriggers=true, then

                                // we do an async postback and refresh the given panel



                                // Although we do the search by looking at ClientIDs, we end

                                // up sending a UniqueID back to the server so that we can

                                // call FindControl() with it.

                                return this._createPostBackSettings(true, [this._updatePanelIDs[indexOfPanel]], elementUniqueID, originalElement);

                            }

                            else {

                                // The element was inside an UpdatePanel so we do an async postback,

                                // but because it has ChildrenAsTriggers=false we don't update this panel.

                                return this._createPostBackSettings(true, null, elementUniqueID, originalElement);

                            }

                        }

                    }

                }



                // Then try near matches

                if (!proposedSettings && this._matchesParentIDInList(element.id, this._asyncPostBackControlClientIDs)) {

                    // The element explicitly causes an async postback

                    proposedSettings = this._createPostBackSettings(true, null, elementUniqueID, originalElement);

                }

                else {

                    if (!proposedSettings && this._matchesParentIDInList(element.id, this._postBackControlClientIDs)) {

                        // The element explicitly doesn't cause an async postback

                        return this._createPostBackSettings(false);

                    }

                }

            }



            element = element.parentNode;

        }



        // If we have proposed settings that means we found a match for an

        // AsyncPostBackControl but were still searching for an UpdatePanel.

        // If we got here that means we didn't find the UpdatePanel so we

        // just fall back to the original AsyncPostBackControl settings that

        // we created.

        if (!proposedSettings) {

            // The element doesn't cause an async postback

            return this._createPostBackSettings(false);

        }

        else {

            return proposedSettings;

        }

    },



    _getScrollPosition: function PageRequestManager$_getScrollPosition() {

        var d = document.documentElement;

        if (d && (this._validPosition(d.scrollLeft) || this._validPosition(d.scrollTop))) {

            return {

                x: d.scrollLeft,

                y: d.scrollTop

            };

        }

        else {

            d = document.body;

            if (d && (this._validPosition(d.scrollLeft) || this._validPosition(d.scrollTop))) {

                return {

                    x: d.scrollLeft,

                    y: d.scrollTop

                };

            }

            else {

                if (this._validPosition(window.pageXOffset) || this._validPosition(window.pageYOffset)) {

                    return {

                        x: window.pageXOffset,

                        y: window.pageYOffset

                    };

                }

                else {

                    return {

                        x: 0,

                        y: 0

                    };

                }

            }

        }

    },



    _initializeInternal: function PageRequestManager$_initializeInternal(scriptManagerID, formElement, updatePanelIDs, asyncPostBackControlIDs, postBackControlIDs, asyncPostBackTimeout, masterPageUniqueID) {

        if (this._prmInitialized) {

            throw Error.invalidOperation(Sys.WebForms.Res.PRM_CannotRegisterTwice);

        }

        this._prmInitialized = true;

        this._masterPageUniqueID = masterPageUniqueID;

        this._scriptManagerID = scriptManagerID;

        this._form = Sys.UI.DomElement.resolveElement(formElement);

        this._onsubmit = this._form.onsubmit;

        this._form.onsubmit = null;

        this._onFormSubmitHandler = Function.createDelegate(this, this._onFormSubmit);

        this._onFormElementClickHandler = Function.createDelegate(this, this._onFormElementClick);

        this._onWindowUnloadHandler = Function.createDelegate(this, this._onWindowUnload);

        Sys.UI.DomEvent.addHandler(this._form, 'submit', this._onFormSubmitHandler);

        Sys.UI.DomEvent.addHandler(this._form, 'click', this._onFormElementClickHandler);

        Sys.UI.DomEvent.addHandler(window, 'unload', this._onWindowUnloadHandler);



        this._originalDoPostBack = window.__doPostBack;

        if (this._originalDoPostBack) {

            window.__doPostBack = Function.createDelegate(this, this._doPostBack);

        }

        this._originalDoPostBackWithOptions = window.WebForm_DoPostBackWithOptions;

        if (this._originalDoPostBackWithOptions) {

            window.WebForm_DoPostBackWithOptions = Function.createDelegate(this, this._doPostBackWithOptions);

        }

        this._originalFireDefaultButton = window.WebForm_FireDefaultButton;

        if (this._originalFireDefaultButton) {

            window.WebForm_FireDefaultButton = Function.createDelegate(this, this._fireDefaultButton);

        }

        this._originalDoCallback = window.WebForm_DoCallback;

        if (this._originalDoCallback) {

            window.WebForm_DoCallback = Function.createDelegate(this, this._doCallback);

        }



        this._pageLoadedHandler = Function.createDelegate(this, this._pageLoadedInitialLoad);

        Sys.UI.DomEvent.addHandler(window, 'load', this._pageLoadedHandler);

        if (updatePanelIDs) {

            this._updateControls(updatePanelIDs, asyncPostBackControlIDs, postBackControlIDs, asyncPostBackTimeout, true);

        }

    },



    _matchesParentIDInList: function PageRequestManager$_matchesParentIDInList(clientID, parentIDList) {

        for (var i = 0, l = parentIDList.length; i < l; i++) {

            if (clientID.startsWith(parentIDList[i] + "_")) {

                return true;

            }

        }

        return false;

    },

    

    _onFormElementActive: function PageRequestManager$_onFormElementActive(element, offsetX, offsetY) {

        // element: the form element that is active

        // offsetX/Y: if the element is an image button, the coordinates of the click

        if (element.disabled) {

            return;

        }



        // Check if the element that was clicked on should cause an async postback

        this._postBackSettings = this._getPostBackSettings(element, element.name);



        if (element.name) {

            // DevDiv Bugs 146697: tagName needs to be case insensitive to work with xhtml content type

            var tagName = element.tagName.toUpperCase();

            if (tagName === 'INPUT') {

                var type = element.type;

                if (type === 'submit') {

                    // DevDiv Bugs 109456: Encode the name as well as the value

                    this._additionalInput = encodeURIComponent(element.name) + '=' + encodeURIComponent(element.value);

                }

                else if (type === 'image') {

                    // DevDiv Bugs 109456: Encode the name as well as the value

                    this._additionalInput = encodeURIComponent(element.name) + '.x=' + offsetX + '&' + encodeURIComponent(element.name) + '.y=' + offsetY;

                }

            }

            else if ((tagName === 'BUTTON') && (element.name.length !== 0) && (element.type === 'submit')) {

                // DevDiv Bugs 109456: Encode the name as well as the value

                this._additionalInput = encodeURIComponent(element.name) + '=' + encodeURIComponent(element.value);

            }

        }

    },



    _onFormElementClick: function PageRequestManager$_onFormElementClick(evt) {

        // flag used by fireDefaultButton to know whether calling click() on the default button raised this event.

        this._activeDefaultButtonClicked = (evt.target === this._activeDefaultButton);

        this._onFormElementActive(evt.target, evt.offsetX, evt.offsetY);

    },



    _onFormSubmit: function PageRequestManager$_onFormSubmit(evt) {

        var i, l, continueSubmit = true,

            isCrossPost = this._isCrossPost;

        // set to false so subsequent posts that don't go through DPWO aren't considered cross post

        this._isCrossPost = false;



        // Call the statically declared form onsubmit statement if there was one

        if (this._onsubmit) {

            continueSubmit = this._onsubmit();

        }



        // If necessary, call dynamically added form onsubmit statements

        if (continueSubmit) {

            for (i = 0, l = this._onSubmitStatements.length; i < l; i++) {

                if (!this._onSubmitStatements[i]()) {

                    continueSubmit = false;

                    break;

                }

            }

        }



        if (!continueSubmit) {

            if (evt) {

                evt.preventDefault();

            }

            return;

        }



        var form = this._form;

        if (isCrossPost) {

            // Allow the default form submit to take place. Since it's a cross-page postback.

            return;

        }



        // DevDiv Bugs 123782

        if (this._activeDefaultButton && !this._activeDefaultButtonClicked) {

            // we are submitting because a default button's click method was called by _fireDefaultButton

            // but calling click() explicitly did not cause a click event or raised it for a different element,

            // so we must manually create the correct postback options.

            // The button was clicked programmatically, so there are no offsetX or offsetY coordinates.

            this._onFormElementActive(this._activeDefaultButton, 0, 0);

        }



        // If the postback happened from outside an update panel, fall back

        // and do a normal postback.

        // Dev10 546632: postBackSettings may not exist in certain scenarios where

        // the form click events are cancelled.

        if (!this._postBackSettings || !this._postBackSettings.async) {

            return;

        }



        // Construct the form body

        var formBody = new Sys.StringBuilder(),

            count = form.elements.length,

            panelID = this._createPanelID(null, this._postBackSettings);

        // DevDiv Bugs 109456: ScriptManager and UpdatePanel IDs should be encoded as well

        formBody.append(panelID);



        for (i = 0; i < count; i++) {

            var element = form.elements[i];

            var name = element.name;

            if (typeof(name) === "undefined" || (name === null) || (name.length === 0) || (name === this._scriptManagerID)) {

                continue;

            }



            // DevDiv Bugs 146697: tagName needs to be case insensitive to work with xhtml content type

            var tagName = element.tagName.toUpperCase();



            if (tagName === 'INPUT') {

                var type = element.type;

                if ((type === 'text') ||

                    (type === 'password') ||

                    (type === 'hidden') ||

                    (((type === 'checkbox') || (type === 'radio')) && element.checked)) {

                    // DevDiv Bugs 109456: Encode the name as well as the value

                    formBody.append(encodeURIComponent(name));

                    formBody.append('=');

                    formBody.append(encodeURIComponent(element.value));

                    formBody.append('&');

                }

            }

            else if (tagName === 'SELECT') {

                var optionCount = element.options.length;

                for (var j = 0; j < optionCount; j++) {

                    var option = element.options[j];

                    if (option.selected) {

                        // DevDiv Bugs 109456: Encode the name as well as the value

                        formBody.append(encodeURIComponent(name));

                        formBody.append('=');

                        formBody.append(encodeURIComponent(option.value));

                        formBody.append('&');

                    }

                }

            }

            else if (tagName === 'TEXTAREA') {

                // DevDiv Bugs 109456: Encode the name as well as the value

                formBody.append(encodeURIComponent(name));

                formBody.append('=');

                formBody.append(encodeURIComponent(element.value));

                formBody.append('&');

            }

        }



        // DevDiv Bugs 188713: Some firewalls strip the X-MicrosoftAjax header, so send a custom form field as well.

        formBody.append("__ASYNCPOST=true&");



        if (this._additionalInput) {

            formBody.append(this._additionalInput);

            this._additionalInput = null;

        }

        

        var request = new Sys.Net.WebRequest();

        var action = form.action;

        if (Sys.Browser.agent === Sys.Browser.InternetExplorer) {

            // DevDiv Bugs 85367: In IE we must encode the path portion of the request because XHR doesn't do it for us.

            // First, we remove the url fragment, which can appear in history-related scenarios

            // but is not relevant to async postbacks.

            var fragmentIndex = action.indexOf('#');

            if (fragmentIndex !== -1) {

                action = action.substr(0, fragmentIndex);

            }

            // We only want to encode the path fragment, not the querystring.

            var queryIndex = action.indexOf('?');

            if (queryIndex !== -1) {

                var path = action.substr(0, queryIndex);

                if (path.indexOf("%") === -1) {

                    // only encode if the path portion is not already encoded

                    // tear off the query, encode, then put the query back

                    action = encodeURI(path) + action.substr(queryIndex);

                }

            }

            else if (action.indexOf("%") === -1) {

                // only encode if the path portion is not already encoded

                action = encodeURI(action);

            }

        }

        request.set_url(action);

        request.get_headers()['X-MicrosoftAjax'] = 'Delta=true';

        request.get_headers()['Cache-Control'] = 'no-cache';

        request.set_timeout(this._asyncPostBackTimeout);

        request.add_completed(Function.createDelegate(this, this._onFormSubmitCompleted));

        request.set_body(formBody.toString());

        // eventArgs var reused for beginRequest below

        var panelsToUpdate, eventArgs;

        panelsToUpdate = this._postBackSettings.panelsToUpdate;

        eventArgs = new Sys.WebForms.InitializeRequestEventArgs(request, this._postBackSettings.sourceElement, panelsToUpdate);

        Sys.Observer.raiseEvent(this, "initializeRequest", eventArgs);

        continueSubmit = !eventArgs.get_cancel();



        if (!continueSubmit) {

            if (evt) {

                evt.preventDefault();

            }

            return;

        }

        

        if (eventArgs && eventArgs._updated) {

            // the initializeRequest event has changed the update panels to update

            panelsToUpdate = eventArgs.get_updatePanelsToUpdate();

            request.set_body(request.get_body().replace(panelID, this._createPanelID(panelsToUpdate, this._postBackSettings)));

        }



        // Save the scroll position

        this._scrollPosition = this._getScrollPosition();





        // If we're going on to make a new request (i.e. the user didn't cancel), and

        // there's still an ongoing request, we have to abort it. If we don't then it

        // will exhaust the browser's two connections per server limit very quickly.

        this.abortPostBack();



        eventArgs = new Sys.WebForms.BeginRequestEventArgs(request, this._postBackSettings.sourceElement,

            panelsToUpdate || this._postBackSettings.panelsToUpdate);

        Sys.Observer.raiseEvent(this, "beginRequest", eventArgs);

        

        // DevDiv Bugs 125825: Cancel any pending callbacks when an async postback begins

        if (this._originalDoCallback) {

            this._cancelPendingCallbacks();

        }



        this._request = request;

        // DevDiv Bugs 154403: A previous request may be loading scripts at this point.

        // If so, once its scripts finish, it will not be processed any further. 

        // We must clear _processingRequest, otherwise in this scenario the 2nd post would

        // not be abortable because it would appear that its response is already received.

        this._processingRequest = false;

        request.invoke();



        // Suppress the default form submit functionality

        if (evt) {

            evt.preventDefault();

        }

    },



    _onFormSubmitCompleted: function PageRequestManager$_onFormSubmitCompleted(sender, eventArgs) {

        // setting this true means the request can no longer be aborted

        this._processingRequest = true;



        // sender is the executor object



        if (sender.get_timedOut()) {

            this._endPostBack(this._createPageRequestManagerTimeoutError(), sender, null);

            return;

        }



        if (sender.get_aborted()) {

            this._endPostBack(null, sender, null);

            return;

        }



        // If the response isn't the response to the latest request, ignore it (last one wins)

        // This can happen if a 2nd async post begins before the response for the 1st is received

        if (!this._request || (sender.get_webRequest() !== this._request)) {

            return;

        }



        // If we have an invalid status code, go into error mode

        if (sender.get_statusCode() !== 200) {

            this._endPostBack(this._createPageRequestManagerServerError(sender.get_statusCode()), sender, null);

            return;

        }



        var data = this._parseDelta(sender);

        if (!data) return;

        

        var i, l;



        if (data.asyncPostBackControlIDsNode && data.postBackControlIDsNode &&

            data.updatePanelIDsNode && data.panelsToRefreshNode && data.childUpdatePanelIDsNode) {

            

            var oldUpdatePanelIDs = this._updatePanelIDs,

                oldUpdatePanelClientIDs = this._updatePanelClientIDs;

            var childUpdatePanelIDsString = data.childUpdatePanelIDsNode.content;

            var childUpdatePanelIDs = childUpdatePanelIDsString.length ? childUpdatePanelIDsString.split(',') : [];



            var asyncPostBackControlIDsArray = this._splitNodeIntoArray(data.asyncPostBackControlIDsNode);

            var postBackControlIDsArray = this._splitNodeIntoArray(data.postBackControlIDsNode);

            var updatePanelIDsArray = this._splitNodeIntoArray(data.updatePanelIDsNode);

            var panelsToRefreshIDs = this._splitNodeIntoArray(data.panelsToRefreshNode);



            // Validate that all the top level UpdatePanels that we plan to update exist

            // in the active document. We do this early so that we can later assume that

            // all referenced UpdatePanels exist.

            var v4 = data.version4;

            for (i = 0, l = panelsToRefreshIDs.length; i < l; i+= (v4 ? 2 : 1)) {

                var panelClientID = (v4 ? panelsToRefreshIDs[i+1] : "") || this._uniqueIDToClientID(panelsToRefreshIDs[i]);

                if (!document.getElementById(panelClientID)) {

                    this._endPostBack(Error.invalidOperation(String.format(Sys.WebForms.Res.PRM_MissingPanel, panelClientID)), sender, data);

                    return;

                }

            }

            

            var updatePanelData = this._processUpdatePanelArrays(

                updatePanelIDsArray,

                asyncPostBackControlIDsArray,

                postBackControlIDsArray, v4);

            updatePanelData.oldUpdatePanelIDs = oldUpdatePanelIDs;

            updatePanelData.oldUpdatePanelClientIDs = oldUpdatePanelClientIDs;

            updatePanelData.childUpdatePanelIDs = childUpdatePanelIDs;

            updatePanelData.panelsToRefreshIDs = panelsToRefreshIDs;

            data.updatePanelData = updatePanelData;

        }



        // Process data items

        data.dataItems = {};

        var node;

        for (i = 0, l = data.dataItemNodes.length; i < l; i++) {

            node = data.dataItemNodes[i];

            data.dataItems[node.id] = node.content;

        }

        for (i = 0, l = data.dataItemJsonNodes.length; i < l; i++) {

            node = data.dataItemJsonNodes[i];

            data.dataItems[node.id] = Sys.Serialization.JavaScriptSerializer.deserialize(node.content);

        }



        var handler = Sys.Observer._getContext(this, true).events.getHandler("pageLoading");

        if (handler) {

            handler(this, this._getPageLoadingEventArgs(data));

        }



        // DevDiv Bugs 127756: Load script includes before updating the HTML.

        // After updating the HTML, load script blocks, startup scripts, hidden fields, arrays, expandos, and onsubmit statements

        // Includes must be loaded first because the new DOM may have inline event handlers declared that depend on new

        // resources in the include files. They may also depend on resources in client script BLOCKS,

        // but script blocks can still load after updating the HTML because they load synchronously,

        // and therefore will still be loaded before any event handlers could fire. They can't be loaded before updating the HTML,

        // because dispose scripts must be executed first in case they dispose of resources declared by the script blocks.

        // Neither can the HTML be disposed of, then scripts loaded, and then the HTML updated, because that would cause a flicker.

        // This means ClientScriptIncludes and ClientScriptBlocks will load disjunct from one another during async updates,

        // but script includes should not depend on script blocks. This mechanism allows inline event handlers, a likely scenario,

        // whereas complex dependencies between script includes and script blocks is uncommon and not recommended.

        // Finally -- startup scripts could contain more script includes, so there are two calls to the script loader, which breaks the

        // completion handling of an async update into 3 separate functions: _onFormSubmitCompleted, _scriptIncludesLoadComplete, _scriptsLoadComplete.



        // DevDiv Bugs 154403: Race condition

        // The fix for 127756 (see above) introduced a race condition. It made it possible for a 2nd async post to

        // begin after the response for the 1st is received but before the HTML is updated, because the page is

        // interactive while scripts are loading. Previously, the HTML was updated immediately when a response was

        // received. This extra gap made it possible for the 2nd post to send stale ViewState and EventValidation data

        // to the server, which would ultimately be replaced by the processing of the 1st response once its scripts

        // have finished loading. A queuing mechanism for async posts cannot work -- because a queued post may

        // originate from HTML that is going to be destroyed or altered by an earlier post still being processed.

        // Instead -- the processing of an async response is altered slightly. Before this fix, once a response is

        // received it was definitely going to be fully processed (all scripts loaded, dom updated, etc). Now, if a

        // 2nd async post begins while scripts are loading for the first, the first response is effectively cancelled.

        // This means it might be possible to load script includes that aren't needed, but this should be harmless.

        // Example:

        // Click [Button1], async post sent to the server. The async response includes a script include [Script1.js],

        // and updated ViewState. PRM begins using the ScriptLoader to load [Script1.js] (it has not updated ViewState

        // yet). While the script is downloading, Click [Button2], which is in a different update panel. Async post is

        // sent to the server with the same ViewState as the first post.

        // Without this fix, Request #1 would continue processing after [Script1.js] has loaded, updating the DOM and

        // ViewState. But then Request #2 would complete with more updated HTML and ViewState. The result would be a

        // page with updated HTML for both UpdatePanels, but only the updated ViewState from the 2nd post.

        // The fix is that when [Script1.js] finishes loading during the processing for Request #1, it is detected

        // that a new request has been made, and no further processing occurs. The only thing Request #1 has caused is

        // its Script Includes to be downloaded, which should be harmless. This also brings the model closer to what it

        // originally was, before the fix for 127756, where it was not possible to perform a post before the viewstate

        // update from a previous post was committed. Note that as always, a 2nd post still cancels the 1st if the

        // response from the 1st is not yet received.

        

        // Read existing script elements (user code may have manually inserted a script element, this will ensure we know about those).

        // This is used to detect duplicates so we don't reload scripts that have already loaded.

        Sys._ScriptLoader.readLoadedScripts();



        // Starting batch mode for component creation to allow for

        // two-pass creation and components that reference each other.

        // endCreateComponents called from _scriptsLoadComplete.

        Sys.Application.beginCreateComponents();



        // First load ClientScriptIncludes

        var scriptLoader = Sys._ScriptLoader.getInstance();

        this._queueScripts(scriptLoader, data.scriptBlockNodes, true, false);

        

        // Save context into a member so that we can later get it from the completion callback

        this._processingRequest = true;



        // PRM does not support load timeout

        //                      timeout, completeCallback, failedCallback, timeoutCallback

        scriptLoader.loadScripts(0,

            Function.createDelegate(this, Function.createCallback(this._scriptIncludesLoadComplete, data)),

            Function.createDelegate(this, Function.createCallback(this._scriptIncludesLoadFailed, data)),

            null);        

    },

    

    _onWindowUnload: function PageRequestManager$_onWindowUnload(evt) {

        this.dispose();

    },



    _pageLoaded: function PageRequestManager$_pageLoaded(initialLoad, data) {

        Sys.Observer.raiseEvent(this, "pageLoaded", this._getPageLoadedEventArgs(initialLoad, data));

        if (!initialLoad) {

            // If this isn't the first page load (i.e. we are doing an async postback), we

            // need to re-raise the Application's load event.

            Sys.Application.raiseLoad();

        }

    },



    _pageLoadedInitialLoad: function PageRequestManager$_pageLoadedInitialLoad(evt) {

        this._pageLoaded(true, null);

    },

    

    _parseDelta: function PageRequestManager$_parseDelta(executor) {

        // General format: length|type|id|content|

        var reply = executor.get_responseData();

        var delimiterIndex, len, type, id, content;

        var replyIndex = 0;

        var parserErrorDetails = null;

        var delta = [];



        while (replyIndex < reply.length) {

            // length| - from index to next delimiter

            delimiterIndex = reply.indexOf('|', replyIndex);

            if (delimiterIndex === -1) {

                parserErrorDetails = this._findText(reply, replyIndex);

                break;

            }

            len = parseInt(reply.substring(replyIndex, delimiterIndex), 10);

            if ((len % 1) !== 0) {

                parserErrorDetails = this._findText(reply, replyIndex);

                break;

            }

            replyIndex = delimiterIndex + 1;



            // type| - from index to next delimiter

            delimiterIndex = reply.indexOf('|', replyIndex);

            if (delimiterIndex === -1) {

                parserErrorDetails = this._findText(reply, replyIndex);

                break;

            }

            type = reply.substring(replyIndex, delimiterIndex);

            replyIndex = delimiterIndex + 1;



            // id| - from index to next delimiter

            delimiterIndex = reply.indexOf('|', replyIndex);

            if (delimiterIndex === -1) {

                parserErrorDetails =