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/*
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* Metadata - jQuery plugin for parsing metadata from elements
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*
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* Copyright (c) 2006 John Resig, Yehuda Katz, J�örn Zaefferer, Paul McLanahan
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*
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* Dual licensed under the MIT and GPL licenses:
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* http://www.opensource.org/licenses/mit-license.php
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* http://www.gnu.org/licenses/gpl.html
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*
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* Revision: $Id$
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*
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*/
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/**
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* Sets the type of metadata to use. Metadata is encoded in JSON, and each property
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* in the JSON will become a property of the element itself.
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*
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* There are three supported types of metadata storage:
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*
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* attr: Inside an attribute. The name parameter indicates *which* attribute.
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*
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* class: Inside the class attribute, wrapped in curly braces: { }
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*
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* elem: Inside a child element (e.g. a script tag). The
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* name parameter indicates *which* element.
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*
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* The metadata for an element is loaded the first time the element is accessed via jQuery.
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*
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* As a result, you can define the metadata type, use $(expr) to load the metadata into the elements
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* matched by expr, then redefine the metadata type and run another $(expr) for other elements.
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*
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* @name $.metadata.setType
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*
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* @example <p id="one" class="some_class {item_id: 1, item_label: 'Label'}">This is a p</p>
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* @before $.metadata.setType("class")
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* @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
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* @desc Reads metadata from the class attribute
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*
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* @example <p id="one" class="some_class" data="{item_id: 1, item_label: 'Label'}">This is a p</p>
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* @before $.metadata.setType("attr", "data")
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* @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
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* @desc Reads metadata from a "data" attribute
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*
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* @example <p id="one" class="some_class"><script>{item_id: 1, item_label: 'Label'}</script>This is a p</p>
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* @before $.metadata.setType("elem", "script")
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* @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"
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* @desc Reads metadata from a nested script element
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*
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* @param String type The encoding type
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* @param String name The name of the attribute to be used to get metadata (optional)
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* @cat Plugins/Metadata
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* @descr Sets the type of encoding to be used when loading metadata for the first time
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* @type undefined
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* @see metadata()
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*/
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(function($) {
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$.extend({
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metadata : {
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defaults : {
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type: 'class',
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name: 'metadata',
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cre: /({.*})/,
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single: 'metadata'
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},
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setType: function( type, name ){
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this.defaults.type = type;
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this.defaults.name = name;
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},
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get: function( elem, opts ){
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var settings = $.extend({},this.defaults,opts);
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// check for empty string in single property
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if ( !settings.single.length ) settings.single = 'metadata';
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var data = $.data(elem, settings.single);
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// returned cached data if it already exists
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if ( data ) return data;
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data = "{}";
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if ( settings.type == "class" ) {
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var m = settings.cre.exec( elem.className );
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if ( m )
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data = m[1];
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} else if ( settings.type == "elem" ) {
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if( !elem.getElementsByTagName )
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return undefined;
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var e = elem.getElementsByTagName(settings.name);
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if ( e.length )
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data = $.trim(e[0].innerHTML);
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} else if ( elem.getAttribute != undefined ) {
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var attr = elem.getAttribute( settings.name );
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if ( attr )
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data = attr;
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}
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if ( data.indexOf( '{' ) <0 )
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data = "{" + data + "}";
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data = eval("(" + data + ")");
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$.data( elem, settings.single, data );
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return data;
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}
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}
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});
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/**
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* Returns the metadata object for the first member of the jQuery object.
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*
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* @name metadata
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* @descr Returns element's metadata object
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* @param Object opts An object contianing settings to override the defaults
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* @type jQuery
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* @cat Plugins/Metadata
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*/
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$.fn.metadata = function( opts ){
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return $.metadata.get( this[0], opts );
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};
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})(jQuery);
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