text: ﻿/**
   * Sets the type of metadata to use. Metadata is encoded in JSON, and each property
   * in the JSON will become a property of the element itself.
   *
   * There are three supported types of metadata storage:
   *
   *   attr:  Inside an attribute. The name parameter indicates *which* attribute.
   *          
   *   class: Inside the class attribute, wrapped in curly braces: { }
   *   
   *   elem:  Inside a child element (e.g. a script tag). The
   *          name parameter indicates *which* element.
   *          
   * The metadata for an element is loaded the first time the element is accessed via jQuery.
   *
   * As a result, you can define the metadata type, use $(expr) to load the metadata into the elements
   * matched by expr, then redefine the metadata type and run another $(expr) for other elements.
   * 
   * @name $.metadata.setType
   *
   * @example <p id="one" class="some_class {item_id: 1, item_label: 'Label'}">This is a p</p>
   * @before $.metadata.setType("class")
   * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
   * @desc Reads metadata from the class attribute
   * 
   * @example <p id="one" class="some_class" data="{item_id: 1, item_label: 'Label'}">This is a p</p>
   * @before $.metadata.setType("attr", "data")
   * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
   * @desc Reads metadata from a "data" attribute
   * 
   * @example <p id="one" class="some_class"><script>{item_id: 1, item_label: 'Label'}</script>This is a p</p>
   * @before $.metadata.setType("elem", "script")
   * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
   * @desc Reads metadata from a nested script element
   * 
   * @param String type The encoding type
   * @param String name The name of the attribute to be used to get metadata (optional)
   * @cat Plugins/Metadata
   * @descr Sets the type of encoding to be used when loading metadata for the first time
   * @type undefined
   * @see metadata()
   */
  
  (function ($) {
  
      $.extend({
          metadata: {
              defaults: {
                  type: 'class',
                  name: 'metadata',
                  cre: /({.*})/,
                  single: 'metadata'
              },
              setType: function (type, name) {
                  this.defaults.type = type;
                  this.defaults.name = name;
              },
              get: function (elem, opts) {
                  var settings = $.extend({}, this.defaults, opts);
                  // check for empty string in single property
                  if (!settings.single.length) settings.single = 'metadata';
  
                  var data = $.data(elem, settings.single);
                  // returned cached data if it already exists
                  if (data) return data;
  
                  data = "{}";
  
                  if (settings.type == "class") {
                      var m = settings.cre.exec(elem.className);
                      if (m)
                          data = m[1];
                  } else if (settings.type == "elem") {
                      if (!elem.getElementsByTagName)
                          return undefined;
                      var e = elem.getElementsByTagName(settings.name);
                      if (e.length)
                          data = $.trim(e[0].innerHTML);
                  } else if (elem.getAttribute != undefined) {
                      var attr = elem.getAttribute(settings.name);
                      if (attr)
                          data = attr;
                  }
  
                  if (data.indexOf('{') < 0)
                      data = "{" + data + "}";
  
                  data = eval("(" + data + ")");
  
                  $.data(elem, settings.single, data);
                  return data;
              }
          }
      });
  
      /**
       * Returns the metadata object for the first member of the jQuery object.
       *
       * @name metadata
       * @descr Returns element's metadata object
       * @param Object opts An object contianing settings to override the defaults
       * @type jQuery
       * @cat Plugins/Metadata
       */
      $.fn.metadata = function (opts) {
          return $.metadata.get(this[0], opts);
      };
  
  })(jQuery);