/user_guide/libraries/form_validation.html

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    186. 

  186. <li class="toctree-l2"><a class="reference internal" href="../helpers/form_helper.html">Form Helper</a></li>
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  210.     <img src="data:image/jpeg;base64,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" title="Toggle Table of Contents" alt="Toggle Table of Contents" />
    211. 

  211.   </a>
    212. 

  212. </div>
    213. 

  213. 

  214.   <div class="wy-grid-for-nav">
    215. 

  215. 

  216.     
    217. 

  217.     <nav data-toggle="wy-nav-shift" class="wy-nav-side">
    218. 

  218.       <div class="wy-side-nav-search">
    219. 

  219.         
    220. 

  220.           <a href="../index.html" class="fa fa-home"> CodeIgniter</a>
    221. 

  221.         
    222. 

  222.         
    223. 

  223. <div role="search">
    224. 

  224.   <form id="rtd-search-form" class="wy-form" action="../search.html" method="get">
    225. 

  225.     <input type="text" name="q" placeholder="Search docs" />
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  226.     <input type="hidden" name="check_keywords" value="yes" />
    227. 

  227.     <input type="hidden" name="area" value="default" />
    228. 

  228.   </form>
    229. 

  229. </div>
    230. 

  230.       </div>
    231. 

  231. 

  232.       <div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
    233. 

  233.         
    234. 

  234.           
    235. 

  235.           
    236. 

  236.               <ul>
    237. 

  237. <li class="toctree-l1"><a class="reference internal" href="../general/welcome.html">Welcome to CodeIgniter</a></li>
    238. 

  238. </ul>
    239. 

  239. <ul>
    240. 

  240. <li class="toctree-l1"><a class="reference internal" href="../installation/index.html">Installation Instructions</a><ul>
    241. 

  241. <li class="toctree-l2"><a class="reference internal" href="../installation/downloads.html">Downloading CodeIgniter</a></li>
    242. 

  242. <li class="toctree-l2"><a class="reference internal" href="../installation/index.html">Installation Instructions</a></li>
    243. 

  243. <li class="toctree-l2"><a class="reference internal" href="../installation/upgrading.html">Upgrading From a Previous Version</a></li>
    244. 

  244. <li class="toctree-l2"><a class="reference internal" href="../installation/troubleshooting.html">Troubleshooting</a></li>
    245. 

  245. </ul>
    246. 

  246. </li>
    247. 

  247. </ul>
    248. 

  248. <ul>
    249. 

  249. <li class="toctree-l1"><a class="reference internal" href="../overview/index.html">CodeIgniter Overview</a><ul>
    250. 

  250. <li class="toctree-l2"><a class="reference internal" href="../overview/getting_started.html">Getting Started</a></li>
    251. 

  251. <li class="toctree-l2"><a class="reference internal" href="../overview/at_a_glance.html">CodeIgniter at a Glance</a></li>
    252. 

  252. <li class="toctree-l2"><a class="reference internal" href="../overview/features.html">Supported Features</a></li>
    253. 

  253. <li class="toctree-l2"><a class="reference internal" href="../overview/appflow.html">Application Flow Chart</a></li>
    254. 

  254. <li class="toctree-l2"><a class="reference internal" href="../overview/mvc.html">Model-View-Controller</a></li>
    255. 

  255. <li class="toctree-l2"><a class="reference internal" href="../overview/goals.html">Architectural Goals</a></li>
    256. 

  256. </ul>
    257. 

  257. </li>
    258. 

  258. </ul>
    259. 

  259. <ul>
    260. 

  260. <li class="toctree-l1"><a class="reference internal" href="../tutorial/index.html">Tutorial</a><ul>
    261. 

  261. <li class="toctree-l2"><a class="reference internal" href="../tutorial/static_pages.html">Static pages</a></li>
    262. 

  262. <li class="toctree-l2"><a class="reference internal" href="../tutorial/news_section.html">News section</a></li>
    263. 

  263. <li class="toctree-l2"><a class="reference internal" href="../tutorial/create_news_items.html">Create news items</a></li>
    264. 

  264. <li class="toctree-l2"><a class="reference internal" href="../tutorial/conclusion.html">Conclusion</a></li>
    265. 

  265. </ul>
    266. 

  266. </li>
    267. 

  267. </ul>
    268. 

  268. <ul>
    269. 

  269. <li class="toctree-l1"><a class="reference internal" href="../contributing/index.html">Contributing to CodeIgniter</a><ul>
    270. 

  270. <li class="toctree-l2"><a class="reference internal" href="../documentation/index.html">Writing CodeIgniter Documentation</a></li>
    271. 

  271. <li class="toctree-l2"><a class="reference internal" href="../DCO.html">Developer’s Certificate of Origin 1.1</a></li>
    272. 

  272. </ul>
    273. 

  273. </li>
    274. 

  274. </ul>
    275. 

  275. <ul>
    276. 

  276. <li class="toctree-l1"><a class="reference internal" href="../general/index.html">General Topics</a><ul>
    277. 

  277. <li class="toctree-l2"><a class="reference internal" href="../general/urls.html">CodeIgniter URLs</a></li>
    278. 

  278. <li class="toctree-l2"><a class="reference internal" href="../general/controllers.html">Controllers</a></li>
    279. 

  279. <li class="toctree-l2"><a class="reference internal" href="../general/reserved_names.html">Reserved Names</a></li>
    280. 

  280. <li class="toctree-l2"><a class="reference internal" href="../general/views.html">Views</a></li>
    281. 

  281. <li class="toctree-l2"><a class="reference internal" href="../general/models.html">Models</a></li>
    282. 

  282. <li class="toctree-l2"><a class="reference internal" href="../general/helpers.html">Helpers</a></li>
    283. 

  283. <li class="toctree-l2"><a class="reference internal" href="../general/libraries.html">Using CodeIgniter Libraries</a></li>
    284. 

  284. <li class="toctree-l2"><a class="reference internal" href="../general/creating_libraries.html">Creating Libraries</a></li>
    285. 

  285. <li class="toctree-l2"><a class="reference internal" href="../general/drivers.html">Using CodeIgniter Drivers</a></li>
    286. 

  286. <li class="toctree-l2"><a class="reference internal" href="../general/creating_drivers.html">Creating Drivers</a></li>
    287. 

  287. <li class="toctree-l2"><a class="reference internal" href="../general/core_classes.html">Creating Core System Classes</a></li>
    288. 

  288. <li class="toctree-l2"><a class="reference internal" href="../general/ancillary_classes.html">Creating Ancillary Classes</a></li>
    289. 

  289. <li class="toctree-l2"><a class="reference internal" href="../general/hooks.html">Hooks - Extending the Framework Core</a></li>
    290. 

  290. <li class="toctree-l2"><a class="reference internal" href="../general/autoloader.html">Auto-loading Resources</a></li>
    291. 

  291. <li class="toctree-l2"><a class="reference internal" href="../general/common_functions.html">Common Functions</a></li>
    292. 

  292. <li class="toctree-l2"><a class="reference internal" href="../general/compatibility_functions.html">Compatibility Functions</a></li>
    293. 

  293. <li class="toctree-l2"><a class="reference internal" href="../general/routing.html">URI Routing</a></li>
    294. 

  294. <li class="toctree-l2"><a class="reference internal" href="../general/errors.html">Error Handling</a></li>
    295. 

  295. <li class="toctree-l2"><a class="reference internal" href="../general/caching.html">Caching</a></li>
    296. 

  296. <li class="toctree-l2"><a class="reference internal" href="../general/profiling.html">Profiling Your Application</a></li>
    297. 

  297. <li class="toctree-l2"><a class="reference internal" href="../general/cli.html">Running via the CLI</a></li>
    298. 

  298. <li class="toctree-l2"><a class="reference internal" href="../general/managing_apps.html">Managing your Applications</a></li>
    299. 

  299. <li class="toctree-l2"><a class="reference internal" href="../general/environments.html">Handling Multiple Environments</a></li>
    300. 

  300. <li class="toctree-l2"><a class="reference internal" href="../general/alternative_php.html">Alternate PHP Syntax for View Files</a></li>
    301. 

  301. <li class="toctree-l2"><a class="reference internal" href="../general/security.html">Security</a></li>
    302. 

  302. <li class="toctree-l2"><a class="reference internal" href="../general/styleguide.html">PHP Style Guide</a></li>
    303. 

  303. </ul>
    304. 

  304. </li>
    305. 

  305. </ul>
    306. 

  306. <ul class="current">
    307. 

  307. <li class="toctree-l1 current"><a class="reference internal" href="index.html">Libraries</a><ul class="current">
    308. 

  308. <li class="toctree-l2"><a class="reference internal" href="benchmark.html">Benchmarking Class</a></li>
    309. 

  309. <li class="toctree-l2"><a class="reference internal" href="caching.html">Caching Driver</a></li>
    310. 

  310. <li class="toctree-l2"><a class="reference internal" href="calendar.html">Calendaring Class</a></li>
    311. 

  311. <li class="toctree-l2"><a class="reference internal" href="cart.html">Shopping Cart Class</a></li>
    312. 

  312. <li class="toctree-l2"><a class="reference internal" href="config.html">Config Class</a></li>
    313. 

  313. <li class="toctree-l2"><a class="reference internal" href="email.html">Email Class</a></li>
    314. 

  314. <li class="toctree-l2"><a class="reference internal" href="encrypt.html">Encrypt Class</a></li>
    315. 

  315. <li class="toctree-l2"><a class="reference internal" href="encryption.html">Encryption Library</a></li>
    316. 

  316. <li class="toctree-l2"><a class="reference internal" href="file_uploading.html">File Uploading Class</a></li>
    317. 

  317. <li class="toctree-l2 current"><a class="current reference internal" href="#">Form Validation</a></li>
    318. 

  318. <li class="toctree-l2"><a class="reference internal" href="ftp.html">FTP Class</a></li>
    319. 

  319. <li class="toctree-l2"><a class="reference internal" href="image_lib.html">Image Manipulation Class</a></li>
    320. 

  320. <li class="toctree-l2"><a class="reference internal" href="input.html">Input Class</a></li>
    321. 

  321. <li class="toctree-l2"><a class="reference internal" href="javascript.html">Javascript Class</a></li>
    322. 

  322. <li class="toctree-l2"><a class="reference internal" href="language.html">Language Class</a></li>
    323. 

  323. <li class="toctree-l2"><a class="reference internal" href="loader.html">Loader Class</a></li>
    324. 

  324. <li class="toctree-l2"><a class="reference internal" href="migration.html">Migrations Class</a></li>
    325. 

  325. <li class="toctree-l2"><a class="reference internal" href="output.html">Output Class</a></li>
    326. 

  326. <li class="toctree-l2"><a class="reference internal" href="pagination.html">Pagination Class</a></li>
    327. 

  327. <li class="toctree-l2"><a class="reference internal" href="parser.html">Template Parser Class</a></li>
    328. 

  328. <li class="toctree-l2"><a class="reference internal" href="security.html">Security Class</a></li>
    329. 

  329. <li class="toctree-l2"><a class="reference internal" href="sessions.html">Session Library</a></li>
    330. 

  330. <li class="toctree-l2"><a class="reference internal" href="table.html">HTML Table Class</a></li>
    331. 

  331. <li class="toctree-l2"><a class="reference internal" href="trackback.html">Trackback Class</a></li>
    332. 

  332. <li class="toctree-l2"><a class="reference internal" href="typography.html">Typography Class</a></li>
    333. 

  333. <li class="toctree-l2"><a class="reference internal" href="unit_testing.html">Unit Testing Class</a></li>
    334. 

  334. <li class="toctree-l2"><a class="reference internal" href="uri.html">URI Class</a></li>
    335. 

  335. <li class="toctree-l2"><a class="reference internal" href="user_agent.html">User Agent Class</a></li>
    336. 

  336. <li class="toctree-l2"><a class="reference internal" href="xmlrpc.html">XML-RPC and XML-RPC Server Classes</a></li>
    337. 

  337. <li class="toctree-l2"><a class="reference internal" href="zip.html">Zip Encoding Class</a></li>
    338. 

  338. </ul>
    339. 

  339. </li>
    340. 

  340. </ul>
    341. 

  341. <ul>
    342. 

  342. <li class="toctree-l1"><a class="reference internal" href="../database/index.html">Database Reference</a><ul>
    343. 

  343. <li class="toctree-l2"><a class="reference internal" href="../database/examples.html">Quick Start: Usage Examples</a></li>
    344. 

  344. <li class="toctree-l2"><a class="reference internal" href="../database/configuration.html">Database Configuration</a></li>
    345. 

  345. <li class="toctree-l2"><a class="reference internal" href="../database/connecting.html">Connecting to a Database</a></li>
    346. 

  346. <li class="toctree-l2"><a class="reference internal" href="../database/queries.html">Running Queries</a></li>
    347. 

  347. <li class="toctree-l2"><a class="reference internal" href="../database/results.html">Generating Query Results</a></li>
    348. 

  348. <li class="toctree-l2"><a class="reference internal" href="../database/helpers.html">Query Helper Functions</a></li>
    349. 

  349. <li class="toctree-l2"><a class="reference internal" href="../database/query_builder.html">Query Builder Class</a></li>
    350. 

  350. <li class="toctree-l2"><a class="reference internal" href="../database/transactions.html">Transactions</a></li>
    351. 

  351. <li class="toctree-l2"><a class="reference internal" href="../database/metadata.html">Getting MetaData</a></li>
    352. 

  352. <li class="toctree-l2"><a class="reference internal" href="../database/call_function.html">Custom Function Calls</a></li>
    353. 

  353. <li class="toctree-l2"><a class="reference internal" href="../database/caching.html">Query Caching</a></li>
    354. 

  354. <li class="toctree-l2"><a class="reference internal" href="../database/forge.html">Database Manipulation with Database Forge</a></li>
    355. 

  355. <li class="toctree-l2"><a class="reference internal" href="../database/utilities.html">Database Utilities Class</a></li>
    356. 

  356. <li class="toctree-l2"><a class="reference internal" href="../database/db_driver_reference.html">Database Driver Reference</a></li>
    357. 

  357. </ul>
    358. 

  358. </li>
    359. 

  359. </ul>
    360. 

  360. <ul>
    361. 

  361. <li class="toctree-l1"><a class="reference internal" href="../helpers/index.html">Helpers</a><ul>
    362. 

  362. <li class="toctree-l2"><a class="reference internal" href="../helpers/array_helper.html">Array Helper</a></li>
    363. 

  363. <li class="toctree-l2"><a class="reference internal" href="../helpers/captcha_helper.html">CAPTCHA Helper</a></li>
    364. 

  364. <li class="toctree-l2"><a class="reference internal" href="../helpers/cookie_helper.html">Cookie Helper</a></li>
    365. 

  365. <li class="toctree-l2"><a class="reference internal" href="../helpers/date_helper.html">Date Helper</a></li>
    366. 

  366. <li class="toctree-l2"><a class="reference internal" href="../helpers/directory_helper.html">Directory Helper</a></li>
    367. 

  367. <li class="toctree-l2"><a class="reference internal" href="../helpers/download_helper.html">Download Helper</a></li>
    368. 

  368. <li class="toctree-l2"><a class="reference internal" href="../helpers/email_helper.html">Email Helper</a></li>
    369. 

  369. <li class="toctree-l2"><a class="reference internal" href="../helpers/file_helper.html">File Helper</a></li>
    370. 

  370. <li class="toctree-l2"><a class="reference internal" href="../helpers/form_helper.html">Form Helper</a></li>
    371. 

  371. <li class="toctree-l2"><a class="reference internal" href="../helpers/html_helper.html">HTML Helper</a></li>
    372. 

  372. <li class="toctree-l2"><a class="reference internal" href="../helpers/inflector_helper.html">Inflector Helper</a></li>
    373. 

  373. <li class="toctree-l2"><a class="reference internal" href="../helpers/language_helper.html">Language Helper</a></li>
    374. 

  374. <li class="toctree-l2"><a class="reference internal" href="../helpers/number_helper.html">Number Helper</a></li>
    375. 

  375. <li class="toctree-l2"><a class="reference internal" href="../helpers/path_helper.html">Path Helper</a></li>
    376. 

  376. <li class="toctree-l2"><a class="reference internal" href="../helpers/security_helper.html">Security Helper</a></li>
    377. 

  377. <li class="toctree-l2"><a class="reference internal" href="../helpers/smiley_helper.html">Smiley Helper</a></li>
    378. 

  378. <li class="toctree-l2"><a class="reference internal" href="../helpers/string_helper.html">String Helper</a></li>
    379. 

  379. <li class="toctree-l2"><a class="reference internal" href="../helpers/text_helper.html">Text Helper</a></li>
    380. 

  380. <li class="toctree-l2"><a class="reference internal" href="../helpers/typography_helper.html">Typography Helper</a></li>
    381. 

  381. <li class="toctree-l2"><a class="reference internal" href="../helpers/url_helper.html">URL Helper</a></li>
    382. 

  382. <li class="toctree-l2"><a class="reference internal" href="../helpers/xml_helper.html">XML Helper</a></li>
    383. 

  383. </ul>
    384. 

  384. </li>
    385. 

  385. </ul>
    386. 

  386. 

  387.           
    388. 

  388.         
    389. 

  389.       </div>
    390. 

  390.       &nbsp;
    391. 

  391.     </nav>
    392. 

  392. 

  393.     <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
    394. 

  394. 

  395.       
    396. 

  396.       <nav class="wy-nav-top" role="navigation" aria-label="top navigation">
    397. 

  397.         <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
    398. 

  398.         <a href="../index.html">CodeIgniter</a>
    399. 

  399.       </nav>
    400. 

  400. 

  401. 

  402.       
    403. 

  403.       <div class="wy-nav-content">
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    405. 

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    406. 

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    407. 

  407.     <li><a href="../index.html">Docs</a> &raquo;</li>
    408. 

  408.       
    409. 

  409.         <li><a href="index.html">Libraries</a> &raquo;</li>
    410. 

  410.       
    411. 

  411.     <li>Form Validation</li>
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    413. 

  413.       
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    415. 

  415.     <div style="float:right;margin-left:5px;" id="closeMe">
    416. 

  416.       <img title="Classic Layout" alt="classic layout" src="data:image/gif;base64,R0lGODlhFAAUAJEAAAAAADMzM////wAAACH5BAUUAAIALAAAAAAUABQAAAImlI+py+0PU5gRBRDM3DxbWoXis42X13USOLauUIqnlsaH/eY6UwAAOw==" />
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    418. 

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    419. 

  419.   <hr/>
    420. 

  420. </div>
    421. 

  421.           <div role="main" class="document">
    422. 

  422.             
    423. 

  423.   <div class="section" id="form-validation">
    424. 

  424. <h1><a class="toc-backref" href="#id6">Form Validation</a><a class="headerlink" href="#form-validation" title="Permalink to this headline"></a></h1>
    425. 

  425. <p>CodeIgniter provides a comprehensive form validation and data prepping
    426. 

  426. class that helps minimize the amount of code you’ll write.</p>
    427. 

  427. <div class="contents topic" id="page-contents">
    428. 

  428. <p class="topic-title first">Page Contents</p>
    429. 

  429. <ul class="simple">
    430. 

  430. <li><a class="reference internal" href="#form-validation" id="id6">Form Validation</a><ul>
    431. 

  431. <li><a class="reference internal" href="#overview" id="id7">Overview</a></li>
    432. 

  432. <li><a class="reference internal" href="#form-validation-tutorial" id="id8">Form Validation Tutorial</a><ul>
    433. 

  433. <li><a class="reference internal" href="#the-form" id="id9">The Form</a></li>
    434. 

  434. <li><a class="reference internal" href="#the-success-page" id="id10">The Success Page</a></li>
    435. 

  435. <li><a class="reference internal" href="#the-controller" id="id11">The Controller</a></li>
    436. 

  436. <li><a class="reference internal" href="#try-it" id="id12">Try it!</a></li>
    437. 

  437. <li><a class="reference internal" href="#explanation" id="id13">Explanation</a></li>
    438. 

  438. <li><a class="reference internal" href="#setting-validation-rules" id="id14">Setting Validation Rules</a></li>
    439. 

  439. <li><a class="reference internal" href="#setting-rules-using-an-array" id="id15">Setting Rules Using an Array</a></li>
    440. 

  440. <li><a class="reference internal" href="#cascading-rules" id="id16">Cascading Rules</a></li>
    441. 

  441. <li><a class="reference internal" href="#prepping-data" id="id17">Prepping Data</a></li>
    442. 

  442. <li><a class="reference internal" href="#re-populating-the-form" id="id18">Re-populating the form</a></li>
    443. 

  443. <li><a class="reference internal" href="#callbacks-your-own-validation-methods" id="id19">Callbacks: Your own Validation Methods</a></li>
    444. 

  444. <li><a class="reference internal" href="#callable-use-anything-as-a-rule" id="id20">Callable: Use anything as a rule</a></li>
    445. 

  445. <li><a class="reference internal" href="#setting-error-messages" id="id21">Setting Error Messages</a></li>
    446. 

  446. <li><a class="reference internal" href="#translating-field-names" id="id22">Translating Field Names</a></li>
    447. 

  447. <li><a class="reference internal" href="#changing-the-error-delimiters" id="id23">Changing the Error Delimiters</a></li>
    448. 

  448. <li><a class="reference internal" href="#showing-errors-individually" id="id24">Showing Errors Individually</a></li>
    449. 

  449. <li><a class="reference internal" href="#validating-an-array-other-than-post" id="id25">Validating an Array (other than $_POST)</a></li>
    450. 

  450. </ul>
    451. 

  451. </li>
    452. 

  452. <li><a class="reference internal" href="#saving-sets-of-validation-rules-to-a-config-file" id="id26">Saving Sets of Validation Rules to a Config File</a><ul>
    453. 

  453. <li><a class="reference internal" href="#how-to-save-your-rules" id="id27">How to save your rules</a></li>
    454. 

  454. <li><a class="reference internal" href="#creating-sets-of-rules" id="id28">Creating Sets of Rules</a></li>
    455. 

  455. <li><a class="reference internal" href="#calling-a-specific-rule-group" id="id29">Calling a Specific Rule Group</a></li>
    456. 

  456. <li><a class="reference internal" href="#associating-a-controller-method-with-a-rule-group" id="id30">Associating a Controller Method with a Rule Group</a></li>
    457. 

  457. </ul>
    458. 

  458. </li>
    459. 

  459. <li><a class="reference internal" href="#using-arrays-as-field-names" id="id31">Using Arrays as Field Names</a></li>
    460. 

  460. <li><a class="reference internal" href="#rule-reference" id="id32">Rule Reference</a></li>
    461. 

  461. <li><a class="reference internal" href="#prepping-reference" id="id33">Prepping Reference</a></li>
    462. 

  462. <li><a class="reference internal" href="#class-reference" id="id34">Class Reference</a></li>
    463. 

  463. <li><a class="reference internal" href="#helper-reference" id="id35">Helper Reference</a></li>
    464. 

  464. </ul>
    465. 

  465. </li>
    466. 

  466. </ul>
    467. 

  467. </div>
    468. 

  468. <div class="section" id="overview">
    469. 

  469. <h2><a class="toc-backref" href="#id7">Overview</a><a class="headerlink" href="#overview" title="Permalink to this headline"></a></h2>
    470. 

  470. <p>Before explaining CodeIgniter’s approach to data validation, let’s
    471. 

  471. describe the ideal scenario:</p>
    472. 

  472. <ol class="arabic simple">
    473. 

  473. <li>A form is displayed.</li>
    474. 

  474. <li>You fill it in and submit it.</li>
    475. 

  475. <li>If you submitted something invalid, or perhaps missed a required
    476. 

  476. item, the form is redisplayed containing your data along with an
    477. 

  477. error message describing the problem.</li>
    478. 

  478. <li>This process continues until you have submitted a valid form.</li>
    479. 

  479. </ol>
    480. 

  480. <p>On the receiving end, the script must:</p>
    481. 

  481. <ol class="arabic simple">
    482. 

  482. <li>Check for required data.</li>
    483. 

  483. <li>Verify that the data is of the correct type, and meets the correct
    484. 

  484. criteria. For example, if a username is submitted it must be
    485. 

  485. validated to contain only permitted characters. It must be of a
    486. 

  486. minimum length, and not exceed a maximum length. The username can’t
    487. 

  487. be someone else’s existing username, or perhaps even a reserved word.
    488. 

  488. Etc.</li>
    489. 

  489. <li>Sanitize the data for security.</li>
    490. 

  490. <li>Pre-format the data if needed (Does the data need to be trimmed? HTML
    491. 

  491. encoded? Etc.)</li>
    492. 

  492. <li>Prep the data for insertion in the database.</li>
    493. 

  493. </ol>
    494. 

  494. <p>Although there is nothing terribly complex about the above process, it
    495. 

  495. usually requires a significant amount of code, and to display error
    496. 

  496. messages, various control structures are usually placed within the form
    497. 

  497. HTML. Form validation, while simple to create, is generally very messy
    498. 

  498. and tedious to implement.</p>
    499. 

  499. </div>
    500. 

  500. <div class="section" id="form-validation-tutorial">
    501. 

  501. <h2><a class="toc-backref" href="#id8">Form Validation Tutorial</a><a class="headerlink" href="#form-validation-tutorial" title="Permalink to this headline"></a></h2>
    502. 

  502. <p>What follows is a “hands on” tutorial for implementing CodeIgniters Form
    503. 

  503. Validation.</p>
    504. 

  504. <p>In order to implement form validation you’ll need three things:</p>
    505. 

  505. <ol class="arabic simple">
    506. 

  506. <li>A <a class="reference internal" href="../general/views.html"><span class="doc">View</span></a> file containing a form.</li>
    507. 

  507. <li>A View file containing a “success” message to be displayed upon
    508. 

  508. successful submission.</li>
    509. 

  509. <li>A <a class="reference internal" href="../general/controllers.html"><span class="doc">controller</span></a> method to receive and
    510. 

  510. process the submitted data.</li>
    511. 

  511. </ol>
    512. 

  512. <p>Let’s create those three things, using a member sign-up form as the
    513. 

  513. example.</p>
    514. 

  514. <div class="section" id="the-form">
    515. 

  515. <h3><a class="toc-backref" href="#id9">The Form</a><a class="headerlink" href="#the-form" title="Permalink to this headline"></a></h3>
    516. 

  516. <p>Using a text editor, create a form called myform.php. In it, place this
    517. 

  517. code and save it to your application/views/ folder:</p>
    518. 

  518. <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="o">&lt;</span><span class="nx">html</span><span class="o">&gt;</span>
    519. 

  519. <span class="o">&lt;</span><span class="nx">head</span><span class="o">&gt;</span>
    520. 

  520. <span class="o">&lt;</span><span class="nx">title</span><span class="o">&gt;</span><span class="nx">My</span> <span class="nx">Form</span><span class="o">&lt;/</span><span class="nx">title</span><span class="o">&gt;</span>
    521. 

  521. <span class="o">&lt;/</span><span class="nx">head</span><span class="o">&gt;</span>
    522. 

  522. <span class="o">&lt;</span><span class="nx">body</span><span class="o">&gt;</span>
    523. 

  523. 

  524. <span class="o">&lt;?</span><span class="nx">php</span> <span class="k">echo</span> <span class="nx">validation_errors</span><span class="p">();</span> <span class="cp">?&gt;</span>
    525. 

  525. 

  526. <span class="cp">&lt;?php</span> <span class="k">echo</span> <span class="nx">form_open</span><span class="p">(</span><span class="s1">&#39;form&#39;</span><span class="p">);</span> <span class="cp">?&gt;</span>
    527. 

  527. 

  528. <span class="p">&lt;</span><span class="nt">h5</span><span class="p">&gt;</span>Username<span class="p">&lt;/</span><span class="nt">h5</span><span class="p">&gt;</span>
    529. 

  529. <span class="p">&lt;</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">&quot;text&quot;</span> <span class="na">name</span><span class="o">=</span><span class="s">&quot;username&quot;</span> <span class="na">value</span><span class="o">=</span><span class="s">&quot;&quot;</span> <span class="na">size</span><span class="o">=</span><span class="s">&quot;50&quot;</span> <span class="p">/&gt;</span>
    530. 

  530. 

  531. <span class="p">&lt;</span><span class="nt">h5</span><span class="p">&gt;</span>Password<span class="p">&lt;/</span><span class="nt">h5</span><span class="p">&gt;</span>
    532. 

  532. <span class="p">&lt;</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">&quot;text&quot;</span> <span class="na">name</span><span class="o">=</span><span class="s">&quot;password&quot;</span> <span class="na">value</span><span class="o">=</span><span class="s">&quot;&quot;</span> <span class="na">size</span><span class="o">=</span><span class="s">&quot;50&quot;</span> <span class="p">/&gt;</span>
    533. 

  533. 

  534. <span class="p">&lt;</span><span class="nt">h5</span><span class="p">&gt;</span>Password Confirm<span class="p">&lt;/</span><span class="nt">h5</span><span class="p">&gt;</span>
    535. 

  535. <span class="p">&lt;</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">&quot;text&quot;</span> <span class="na">name</span><span class="o">=</span><span class="s">&quot;passconf&quot;</span> <span class="na">value</span><span class="o">=</span><span class="s">&quot;&quot;</span> <span class="na">size</span><span class="o">=</span><span class="s">&quot;50&quot;</span> <span class="p">/&gt;</span>
    536. 

  536. 

  537. <span class="p">&lt;</span><span class="nt">h5</span><span class="p">&gt;</span>Email Address<span class="p">&lt;/</span><span class="nt">h5</span><span class="p">&gt;</span>
    538. 

  538. <span class="p">&lt;</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">&quot;text&quot;</span> <span class="na">name</span><span class="o">=</span><span class="s">&quot;email&quot;</span> <span class="na">value</span><span class="o">=</span><span class="s">&quot;&quot;</span> <span class="na">size</span><span class="o">=</span><span class="s">&quot;50&quot;</span> <span class="p">/&gt;</span>
    539. 

  539. 

  540. <span class="p">&lt;</span><span class="nt">div</span><span class="p">&gt;&lt;</span><span class="nt">input</span> <span class="na">type</span><span class="o">=</span><span class="s">&quot;submit&quot;</span> <span class="na">value</span><span class="o">=</span><span class="s">&quot;Submit&quot;</span> <span class="p">/&gt;&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
    541. 

  541. 

  542. <span class="p">&lt;/</span><span class="nt">form</span><span class="p">&gt;</span>
    543. 

  543. 

  544. <span class="p">&lt;/</span><span class="nt">body</span><span class="p">&gt;</span>
    545. 

  545. <span class="p">&lt;/</span><span class="nt">html</span><span class="p">&gt;</span>
    546. 

  546. </pre></div>
    547. 

  547. </div>
    548. 

  548. </div>
    549. 

  549. <div class="section" id="the-success-page">
    550. 

  550. <h3><a class="toc-backref" href="#id10">The Success Page</a><a class="headerlink" href="#the-success-page" title="Permalink to this headline"></a></h3>
    551. 

  551. <p>Using a text editor, create a form called formsuccess.php. In it, place
    552. 

  552. this code and save it to your application/views/ folder:</p>
    553. 

  553. <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="o">&lt;</span><span class="nx">html</span><span class="o">&gt;</span>
    554. 

  554. <span class="o">&lt;</span><span class="nx">head</span><span class="o">&gt;</span>
    555. 

  555. <span class="o">&lt;</span><span class="nx">title</span><span class="o">&gt;</span><span class="nx">My</span> <span class="nx">Form</span><span class="o">&lt;/</span><span class="nx">title</span><span class="o">&gt;</span>
    556. 

  556. <span class="o">&lt;/</span><span class="nx">head</span><span class="o">&gt;</span>
    557. 

  557. <span class="o">&lt;</span><span class="nx">body</span><span class="o">&gt;</span>
    558. 

  558. 

  559. <span class="o">&lt;</span><span class="nx">h3</span><span class="o">&gt;</span><span class="nx">Your</span> <span class="nx">form</span> <span class="nx">was</span> <span class="nx">successfully</span> <span class="nx">submitted</span><span class="o">!&lt;/</span><span class="nx">h3</span><span class="o">&gt;</span>
    560. 

  560. 

  561. <span class="o">&lt;</span><span class="nx">p</span><span class="o">&gt;&lt;?</span><span class="nx">php</span> <span class="k">echo</span> <span class="nx">anchor</span><span class="p">(</span><span class="s1">&#39;form&#39;</span><span class="p">,</span> <span class="s1">&#39;Try it again!&#39;</span><span class="p">);</span> <span class="cp">?&gt;</span><span class="p">&lt;/</span><span class="nt">p</span><span class="p">&gt;</span>
    562. 

  562. 

  563. <span class="p">&lt;/</span><span class="nt">body</span><span class="p">&gt;</span>
    564. 

  564. <span class="p">&lt;/</span><span class="nt">html</span><span class="p">&gt;</span>
    565. 

  565. </pre></div>
    566. 

  566. </div>
    567. 

  567. </div>
    568. 

  568. <div class="section" id="the-controller">
    569. 

  569. <h3><a class="toc-backref" href="#id11">The Controller</a><a class="headerlink" href="#the-controller" title="Permalink to this headline"></a></h3>
    570. 

  570. <p>Using a text editor, create a controller called Form.php. In it, place
    571. 

  571. this code and save it to your application/controllers/ folder:</p>
    572. 

  572. <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="o">&lt;?</span><span class="nx">php</span>
    573. 

  573. 

  574. <span class="k">class</span> <span class="nc">Form</span> <span class="k">extends</span> <span class="nx">CI_Controller</span> <span class="p">{</span>
    575. 

  575. 

  576.         <span class="k">public</span> <span class="k">function</span> <span class="nf">index</span><span class="p">()</span>
    577. 

  577.         <span class="p">{</span>
    578. 

  578.                 <span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">helper</span><span class="p">(</span><span class="k">array</span><span class="p">(</span><span class="s1">&#39;form&#39;</span><span class="p">,</span> <span class="s1">&#39;url&#39;</span><span class="p">));</span>
    579. 

  579. 

  580.                 <span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">library</span><span class="p">(</span><span class="s1">&#39;form_validation&#39;</span><span class="p">);</span>
    581. 

  581. 

  582.                 <span class="k">if</span> <span class="p">(</span><span class="nv">$this</span><span class="o">-&gt;</span><span class="na">form_validation</span><span class="o">-&gt;</span><span class="na">run</span><span class="p">()</span> <span class="o">==</span> <span class="k">FALSE</span><span class="p">)</span>
    583. 

  583.                 <span class="p">{</span>
    584. 

  584.                         <span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">view</span><span class="p">(</span><span class="s1">&#39;myform&#39;</span><span class="p">);</span>
    585. 

  585.                 <span class="p">}</span>
    586. 

  586.                 <span class="k">else</span>
    587. 

  587.                 <span class="p">{</span>
    588. 

  588.                         <span class="nv">$this</span><span class="o">-&gt;</span><span class="na">load</span><span class="o">-&gt;</span><span class="na">view</span><span class="p">(</span><span class="s1">&#39;formsuccess&#39;</span><span class="p">);</span>
    589. 

  589.                 <span class="p">}</span>
    590. 

  590.         <span class="p">}</span>
    591. 

  591. <span class="p">}</span>
    592. 

  592. </pre></div>
    593. 

  593. </div>
    594. 

  594. </div>
    595. 

  595. <div class="section" id="try-it">
    596. 

  596. <h3><a class="toc-backref" href="#id12">Try it!</a><a class="headerlink" href="#try-it" title="Permalink to this headline"></a></h3>
    597. 

  597. <p>To try your form, visit your site using a URL similar to this one:</p>
    598. 

  598. <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="nx">example</span><span class="o">.</span><span class="nx">com</span><span class="o">/</span><span class="nx">index</span><span class="o">.</span><span class="nx">php</span><span class="o">/</span><span class="nx">form</span><span class="o">/</span>
    599. 

  599. </pre></div>
    600. 

  600. </div>
    601. 

  601. <p>If you submit the form you should simply see the form reload. That’s
    602. 

  602. because you haven’t set up any validation rules yet.</p>
    603. 

  603. <p><strong>Since you haven’t told the Form Validation class to validate anything
    604. 

  604. yet, it returns FALSE (boolean false) by default. ``The run()`` method
    605. 

  605. only returns TRUE if it has successfully applied your rules without any
    606. 

  606. of them failing.</strong></p>
    607. 

  607. </div>
    608. 

  608. <div class="section" id="explanation">
    609. 

  609. <h3><a class="toc-backref" href="#id13">Explanation</a><a class="headerlink" href="#explanation" title="Permalink to this headline"></a></h3>
    610. 

  610. <p>You’ll notice several things about the above pages:</p>
    611. 

  611. <p>The form (myform.php) is a standard web form with a couple exceptions:</p>
    612. 

  612. <ol class="arabic">
    613. 

  613. <li><p class="first">It uses a form helper to create the form opening. Technically, this
    614. 

  614. isn’t necessary. You could create the form using standard HTML.
    615. 

  615. However, the benefit of using the helper is that it generates the
    616. 

  616. action URL for you, based on the URL in your config file. This makes
    617. 

  617. your application more portable in the event your URLs change.</p>
    618. 

  618. </li>
    619. 

  619. <li><p class="first">At the top of the form you’ll notice the following function call:</p>
    620. 

  620. <div class="highlight-ci"><div class="highlight"><pre><span></span><span class="o">&lt;?</span><span class="nx">php</span> <span class="k">echo</span> <span class="nx">validation_errors</span><span class="p">();</span> <span class="cp">?&gt;</span>
    621. 

  621. </pre></div>
    622. 

  622. </div>
    623. 

  623. <p>This function will return any error messages sent back by the
    624. 

  624. validator. If there are no messages it returns an empty string.</p>
    625. 

  625. </li>
    626. 

  626. </ol>
    627. 

  627. <p>The controller (Form.php) has one method: <code class="docutils literal"><span class="pre">index()</span></code>. This method
    628. 

  628. initializes the validation class and loads the form helper and URL
    629. 

  629. helper used by your view files. It also runs the validation routine.
    630. 

  630. Based on whether the validation was successful it either presents the
    631. 

  631. form or the success page.<…
    632.