/*
 * 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);