// version: beta

// created: 2005-08-30

// updated: 2005-08-31

// mredkj.com



function extractNumber(obj, decimalPlaces, allowNegative)

{

	var temp = obj.value;

	

	// avoid changing things if already formatted correctly

	var reg0Str = '[0-9]*';

	if (decimalPlaces > 0) {

		reg0Str += '\\.?[0-9]{0,' + decimalPlaces + '}';

	} else if (decimalPlaces < 0) {

		reg0Str += '\\.?[0-9]*';

	}

	reg0Str = allowNegative ? '^-?' + reg0Str : '^' + reg0Str;

	reg0Str = reg0Str + '$';

	var reg0 = new RegExp(reg0Str);

	if (reg0.test(temp)) return true;



	// first replace all non numbers

	var reg1Str = '[^0-9' + (decimalPlaces != 0 ? '.' : '') + (allowNegative ? '-' : '') + ']';

	var reg1 = new RegExp(reg1Str, 'g');

	temp = temp.replace(reg1, '');



	if (allowNegative) {

		// replace extra negative

		var hasNegative = temp.length > 0 && temp.charAt(0) == '-';

		var reg2 = /-/g;

		temp = temp.replace(reg2, '');

		if (hasNegative) temp = '-' + temp;

	}

	

	if (decimalPlaces != 0) {

		var reg3 = /\./g;

		var reg3Array = reg3.exec(temp);

		if (reg3Array != null) {

			// keep only first occurrence of .

			//  and the number of places specified by decimalPlaces or the entire string if decimalPlaces < 0

			var reg3Right = temp.substring(reg3Array.index + reg3Array[0].length);

			reg3Right = reg3Right.replace(reg3, '');

			reg3Right = decimalPlaces > 0 ? reg3Right.substring(0, decimalPlaces) : reg3Right;

			temp = temp.substring(0,reg3Array.index) + '.' + reg3Right;

		}

	}

	

	obj.value = temp;

}





function blockNonNumbers(obj, e, allowDecimal, allowNegative)

{

	var key;

	var isCtrl = false;

	var keychar;

	var reg;

		

	if(window.event) {

		key = e.keyCode;

		isCtrl = window.event.ctrlKey

	}

	else if(e.which) {

		key = e.which;

		isCtrl = e.ctrlKey;

	}

	

	if (isNaN(key)) return true;

	

	keychar = String.fromCharCode(key);

	

	// check for backspace or delete, or if Ctrl was pressed

	if (key == 8 || isCtrl)

	{

		return true;

	}



	reg = /\d/;

	var isFirstN = allowNegative ? keychar == '-' && obj.value.indexOf('-') == -1 : false;

	var isFirstD = allowDecimal ? keychar == '.' && obj.value.indexOf('.') == -1 : false;

	

	return isFirstN || isFirstD || reg.test(keychar);

}