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   1  /*�örn Zaefferer, Paul McLanahan

   2   *

   3   * Dual licensed under the MIT and GPL licenses:

   4   *   http://www.opensource.org/licenses/mit-license.php

   5   *   http://www.gnu.org/licenses/gpl.html

   6   *

   7   * Revision: $Id: jquery.MetaData.js 16 2012-07-19 11:20:56Z diego.alto $

   8   *

   9   */
  10  
  11  /**

  12   * Sets the type of metadata to use. Metadata is encoded in JSON, and each property

  13   * in the JSON will become a property of the element itself.

  14   *

  15   * There are three supported types of metadata storage:

  16   *

  17   *   attr:  Inside an attribute. The name parameter indicates *which* attribute.

  18   *          

  19   *   class: Inside the class attribute, wrapped in curly braces: { }

  20   *   

  21   *   elem:  Inside a child element (e.g. a script tag). The

  22   *          name parameter indicates *which* element.

  23   *          

  24   * The metadata for an element is loaded the first time the element is accessed via jQuery.

  25   *

  26   * As a result, you can define the metadata type, use $(expr) to load the metadata into the elements

  27   * matched by expr, then redefine the metadata type and run another $(expr) for other elements.

  28   * 

  29   * @name $.metadata.setType

  30   *

  31   * @example <p id="one" class="some_class {item_id: 1, item_label: 'Label'}">This is a p</p>

  32   * @before $.metadata.setType("class")

  33   * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

  34   * @desc Reads metadata from the class attribute

  35   * 

  36   * @example <p id="one" class="some_class" data="{item_id: 1, item_label: 'Label'}">This is a p</p>

  37   * @before $.metadata.setType("attr", "data")

  38   * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

  39   * @desc Reads metadata from a "data" attribute

  40   * 

  41   * @example <p id="one" class="some_class"><script>{item_id: 1, item_label: 'Label'}</script>This is a p</p>

  42   * @before $.metadata.setType("elem", "script")

  43   * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

  44   * @desc Reads metadata from a nested script element

  45   * 

  46   * @param String type The encoding type

  47   * @param String name The name of the attribute to be used to get metadata (optional)

  48   * @cat Plugins/Metadata

  49   * @descr Sets the type of encoding to be used when loading metadata for the first time

  50   * @type undefined

  51   * @see metadata()

  52   */
  53  
  54  (function($) {
  55  
  56  $.extend({
  57      metadata : {
  58          defaults : {
  59              type: 'class',
  60              name: 'metadata',
  61              cre: /({.*})/,
  62              single: 'metadata'
  63          },
  64          setType: function( type, name ){
  65              this.defaults.type = type;
  66              this.defaults.name = name;
  67          },
  68          get: function( elem, opts ){
  69              var settings = $.extend({},this.defaults,opts);
  70              // check for empty string in single property

  71              if ( !settings.single.length ) settings.single = 'metadata';
  72              
  73              var data = $.data(elem, settings.single);
  74              // returned cached data if it already exists

  75              if ( data ) return data;
  76              
  77              data = "{}";
  78              
  79              if ( settings.type == "class" ) {
  80                  var m = settings.cre.exec( elem.className );
  81                  if ( m )
  82                      data = m[1];
  83              } else if ( settings.type == "elem" ) {
  84                  if( !elem.getElementsByTagName )
  85                      return undefined;
  86                  var e = elem.getElementsByTagName(settings.name);
  87                  if ( e.length )
  88                      data = $.trim(e[0].innerHTML);
  89              } else if ( elem.getAttribute != undefined ) {
  90                  var attr = elem.getAttribute( settings.name );
  91                  if ( attr )
  92                      data = attr;
  93              }
  94              
  95              if ( data.indexOf( '{' ) <0 )
  96              data = "{" + data + "}";
  97              
  98              data = eval("(" + data + ")");
  99              
 100              $.data( elem, settings.single, data );
 101              return data;
 102          }
 103      }
 104  });
 105  
 106  /**

 107   * Returns the metadata object for the first member of the jQuery object.

 108   *

 109   * @name metadata

 110   * @descr Returns element's metadata object

 111   * @param Object opts An object contianing settings to override the defaults

 112   * @type jQuery

 113   * @cat Plugins/Metadata

 114   */
 115  $.fn.metadata = function( opts ){
 116      return $.metadata.get( this[0], opts );
 117  };
 118  
 119  })(jQuery);