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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, Jörn 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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 */
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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 data, m, e, attr,
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				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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			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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				m = settings.cre.exec( elem.className );
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				if ( m ) { data = m[1]; }
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			} else if ( settings.type === "elem" ) {
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				if( !elem.getElementsByTagName ) { return undefined; }
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				e = elem.getElementsByTagName(settings.name);
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				if ( e.length ) { data = $.trim(e[0].innerHTML); }
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			} else if ( elem.getAttribute !== undefined ) {
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				attr = elem.getAttribute( settings.name );
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				if ( attr ) { data = attr; }
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			}
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			if ( data.indexOf( '{' ) <0 ) { data = "{" + data + "}"; }
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			/*jshint evil:true */
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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);