ÿþ/*

* Metadata - jQuery plugin for parsing metadata from elements

*

* Copyright (c) 2006 John Resig, Yehuda Katz, Jýÿörn Zaefferer, Paul McLanahan

*

* Dual licensed under the MIT and GPL licenses:

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

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

*

* Revision: $Id$

*

*/



/**

* 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);