ÿþ/*

* Metadata - jQuery plugin for parsing metadata from elements

*

* Copyright (c) 2006 John Resig, Yehuda Katz, Jörn 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: jquery.metadata.js 3640 2007-10-11 18:34:38Z pmclanahan $

*

*/



/**

 * 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;

 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);