/*
 * jQuery Example Plugin 1.3.3
 * 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');
 *  });
 *  $('textarea#message').example('Type your message here', {
 *    class_name: 'example_text',
 *    hide_label: true
 *  });
 *
 * Copyright (c) Paul Mucur (http://mucur.name), 2007-2008.
 * Dual-licensed under the BSD (BSD-LICENSE.txt) and GPL (GPL-LICENSE.txt)
 * licenses.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */
(function($) {
      
  $.fn.example = function(text, args) {
    
    /* Merge the default options with the given arguments. */
    var options = $.extend({}, $.fn.example.defaults, args);
    
    /* Only calculate once whether a callback has been used. */
    var callback = $.isFunction(text);
    
	$.fn.example.bound_class_names[options.class_name] = true;      
    
	// add submit bindings to empty the example fields (we don't want example texts to be submitted)
	$('form:not(.jq_example_form)').addClass('jq_example_form').bind('submit.jq_example', $.fn.example.empty_bound_inputs);
    
	return this.each(function() {
      
      /* Reduce method calls by saving the current jQuery object. */
      var $this = $(this);
      var val = callback ? text.call(this) : text;
	  
	  if (!val) return this;
	  
      /* 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.
       *
       * The trick is to see whether a value has been set that is
       * different to the defaultValue attribute. As I do not want
       * to recklessly clear form inputs that are not examples on
       * document ready, only those with values that match the example
       * text will be cleared.
       *
       * If a callback is used, it is not possible 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 this technique.
       */
      if ($.browser.msie && !$this.attr('defaultValue') &&
          (callback ? $this.val() != '' : $this.val() == text)) {
        $this.val('');
      }

      /* Initially place the example text in the field if it is empty. */
      if ($this.val() == '') {
        $this.addClass(options.class_name);
        
        /* The text argument can now be a function; if this is the case,
         * call it, passing the current element as `this`.
         */
        $this.val(callback ? text.call(this) : text);
      }
    
      /* DEPRECATION WARNING: I am considering removing this option.
       *
       * If the option is set, hide the associated label (and its line-break
       * if it has one).
       */
      if (options.hide_label) {
        var label = $('label[@for=' + $this.attr('id') + ']');
        
        /* The label and its line break must be hidden separately as
         * jQuery 1.1 does not support andSelf().
         */
        label.next('br').hide();
        label.hide();
      }
    
      /* 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('.' + options.class_name)) {
          $(this).val('');
          $(this).removeClass(options.class_name);
        }
      });
    	
      /* Make the example text reappear if the input is blank on blurring. */
      $this.blur(function(e) {
		if ($(this).val() == '') {
		  $(this).addClass(options.class_name);
		  
		  /* 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(callback ? text.call(this) : text);
		}
      });
    });
};
  
  /* Users can override the defaults for the plugin like so:
   *
   *   $.fn.example.defaults.class_name = 'not_example';
   *   $.fn.example.defaults.hide_label = true;
   */
  $.fn.example.defaults = {
    class_name: 'example',
    
    /* DEPRECATION WARNING: I am considering removing this option. */    
    hide_label: false
  };
  
	/* All the class names used are stored as keys in the following array. */
	$.fn.example.bound_class_names = {};
  
	$.fn.example.empty_bound_inputs = function() {
		var self = $(this);
		$.each($.fn.example.bound_class_names, function(key, b) {
			self.find('.' + key).val('');
		});
	}
	
	// empty the processed forms because of FF caching issue
	$(window).unload(function() {
		$.fn.example.empty_bound_inputs.apply($('form.jq_example_form'));
	});

})(jQuery);