/*

 * jQuery Form Example Plugin 1.4.2

 * Populate form inputs with example text that disappears on focus.

 *

 * e.g.

 *  $('input#name').example('Bob Smith');

 *  $('input[@title]').example(function() {

 *    return $(this).attr('title');

 *  });

 *  $('textarea#message').example('Type your message here', {

 *    className: 'example_text'

 *  });

 *

 * Copyright (c) Paul Mucur (http://mucur.name), 2007-2008.

 * Dual-licensed under the BSD (BSD-LICENSE.txt) and GPL (GPL-LICENSE.txt)

 * licenses.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

(function($) {

  

  $.fn.example = function(text, args) {

    

    /* Only calculate once whether a callback has been used. */

    var isCallback = $.isFunction(text);

    

    /* Merge the arguments and given example text into one options object. */

    var options = $.extend({}, args, {example: text});

    

    return this.each(function() {

      

      /* Reduce method calls by saving the current jQuery object. */

      var $this = $(this);

      

      /* Merge the plugin defaults with the given options and, if present,

       * any metadata.

       */

      if ($.metadata) {        

        var o = $.extend({}, $.fn.example.defaults, $this.metadata(), options);

      } else {

        var o = $.extend({}, $.fn.example.defaults, options);

      }

      

      /* The following event handlers only need to be bound once

       * per class name. In order to do this, an array of used

       * class names is stored and checked on each use of the plugin.

       * If the class name is in the array then this whole section 

       * is skipped. If not, the events are bound and the class name 

       * added to the array.

       *

       * As of 1.3.2, the class names are stored as keys in the

       * array, rather than as elements. This removes the need for

       * $.inArray().

       */

      if (!$.fn.example.boundClassNames[o.className]) {

      

        /* Because Gecko-based browsers cache form values

         * but ignore all other attributes such as class, all example

         * values must be cleared on page unload to prevent them from

         * being saved.

         */

        $(window).unload(function() {

          $('.' + o.className).val('');

        });

      

        /* Clear fields that are still examples before any form is submitted

         * otherwise those examples will be sent along as well.

         * 

         * Prior to 1.3, this would only be bound to forms that were

         * parents of example fields but this meant that a page with

         * multiple forms would not work correctly.

         */

        $('form').submit(function() {

        

          /* Clear only the fields inside this particular form. */

          $(this).find('.' + o.className).val('');

        });

      

        /* Add the class name to the array. */

        $.fn.example.boundClassNames[o.className] = true;

      }

    

      /* Internet Explorer will cache form values even if they are cleared

       * on unload, so this will clear any value that matches the example

       * text and hasn't been specified in the value attribute.

       *

       * If a callback is used, it is not possible or safe to predict

       * what the example text is going to be so all non-default values

       * are cleared. This means that caching is effectively disabled for

       * that field.

       *

       * Many thanks to Klaus Hartl for helping resolve this issue.

       */

      if ($.browser.msie && !$this.attr('defaultValue') && (isCallback || $this.val() == o.example))

        $this.val('');

      

      /* Initially place the example text in the field if it is empty

       * and doesn't have focus yet.

       */

      if ($this.val() == '' && this != document.activeElement) {

        $this.addClass(o.className);

        

        /* The text argument can now be a function; if this is the case,

         * call it, passing the current element as `this`.

         */

        $this.val(isCallback ? o.example.call(this) : o.example);

      }

      

      /* Make the example text disappear when someone focuses.

       *

       * To determine whether the value of the field is an example or not,

       * check for the example class name only; comparing the actual value

       * seems wasteful and can stop people from using example values as real 

       * input.

       */

      $this.focus(function() {

        

        /* jQuery 1.1 has no hasClass(), so is() must be used instead. */

        if ($(this).is('.' + o.className)) {

          $(this).val('');

          $(this).removeClass(o.className);

        }

      });



      /* Detect a change event to the field and remove the example class. */

      $this.change(function() {

        if ($(this).is('.' + o.className)) {

          $(this).removeClass(o.className);

        }

      });



      /* Make the example text reappear if the input is blank on blurring. */

      $this.blur(function() {

        if ($(this).val() == '') {

          $(this).addClass(o.className);

          

          /* Re-evaluate the callback function every time the user

           * blurs the field without entering anything. While this

           * is not as efficient as caching the value, it allows for

           * more dynamic applications of the plugin.

           */

          $(this).val(isCallback ? o.example.call(this) : o.example);

        }

      });

    });

  };

  

  /* Users can override the defaults for the plugin like so:

   *

   *   $.fn.example.defaults.className = 'not_example';

   */

  $.fn.example.defaults = {

    className: 'example'

  };

  

  /* All the class names used are stored as keys in the following array. */

  $.fn.example.boundClassNames = [];

  

})(jQuery);