2 * Metadata - jQuery plugin for parsing metadata from elements
4 * Copyright (c) 2006 John Resig, Yehuda Katz, Jörn Zaefferer, Paul McLanahan
6 * Dual licensed under the MIT and GPL licenses:
7 * http://www.opensource.org/licenses/mit-license.php
8 * http://www.gnu.org/licenses/gpl.html
13 * Sets the type of metadata to use. Metadata is encoded in JSON, and each property
14 * in the JSON will become a property of the element itself.
16 * There are three supported types of metadata storage:
18 * attr: Inside an attribute. The name parameter indicates *which* attribute.
20 * class: Inside the class attribute, wrapped in curly braces: { }
22 * elem: Inside a child element (e.g. a script tag). The
23 * name parameter indicates *which* element.
25 * The metadata for an element is loaded the first time the element is accessed via jQuery.
27 * As a result, you can define the metadata type, use $(expr) to load the metadata into the elements
28 * matched by expr, then redefine the metadata type and run another $(expr) for other elements.
30 * @name $.metadata.setType
32 * @example <p id="one" class="some_class {item_id: 1, item_label: 'Label'}">This is a p</p>
33 * @before $.metadata.setType("class")
34 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
35 * @desc Reads metadata from the class attribute
37 * @example <p id="one" class="some_class" data="{item_id: 1, item_label: 'Label'}">This is a p</p>
38 * @before $.metadata.setType("attr", "data")
39 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
40 * @desc Reads metadata from a "data" attribute
42 * @example <p id="one" class="some_class"><script>{item_id: 1, item_label: 'Label'}</script>This is a p</p>
43 * @before $.metadata.setType("elem", "script")
44 * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
45 * @desc Reads metadata from a nested script element
47 * @param String type The encoding type
48 * @param String name The name of the attribute to be used to get metadata (optional)
49 * @cat Plugins/Metadata
50 * @descr Sets the type of encoding to be used when loading metadata for the first time
65 setType: function( type, name ){
66 this.defaults.type = type;
67 this.defaults.name = name;
69 get: function( elem, opts ){
71 settings = $.extend({},this.defaults,opts);
72 // check for empty string in single property
73 if ( !settings.single.length ) { settings.single = 'metadata'; }
75 data = $.data(elem, settings.single);
76 // returned cached data if it already exists
77 if ( data ) { return data; }
81 if ( settings.type === "class" ) {
82 m = settings.cre.exec( elem.className );
83 if ( m ) { data = m[1]; }
84 } else if ( settings.type === "elem" ) {
85 if( !elem.getElementsByTagName ) { return undefined; }
86 e = elem.getElementsByTagName(settings.name);
87 if ( e.length ) { data = $.trim(e[0].innerHTML); }
88 } else if ( elem.getAttribute !== undefined ) {
89 attr = elem.getAttribute( settings.name );
90 if ( attr ) { data = attr; }
93 if ( data.indexOf( '{' ) <0 ) { data = "{" + data + "}"; }
95 data = eval("(" + data + ")");
97 $.data( elem, settings.single, data );
104 * Returns the metadata object for the first member of the jQuery object.
107 * @descr Returns element's metadata object
108 * @param Object opts An object contianing settings to override the defaults
110 * @cat Plugins/Metadata
112 $.fn.metadata = function( opts ){
113 return $.metadata.get( this[0], opts );