1 /*

     2  * Metadata - jQuery plugin for parsing metadata from elements

     3  *

     4  * Copyright (c) 2006 John Resig, Yehuda Katz, J�örn Zaefferer, Paul McLanahan

     5  *

     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

     9  *

    10  * Revision: $Id: jquery.metadata.js 4187 2007-12-16 17:15:27Z joern.zaefferer $

    11  *

    12  */

    13 

    14 /**

    15  * Sets the type of metadata to use. Metadata is encoded in JSON, and each property

    16  * in the JSON will become a property of the element itself.

    17  *

    18  * There are three supported types of metadata storage:

    19  *

    20  *   attr:  Inside an attribute. The name parameter indicates *which* attribute.

    21  *          

    22  *   class: Inside the class attribute, wrapped in curly braces: { }

    23  *   

    24  *   elem:  Inside a child element (e.g. a script tag). The

    25  *          name parameter indicates *which* element.

    26  *          

    27  * The metadata for an element is loaded the first time the element is accessed via jQuery.

    28  *

    29  * As a result, you can define the metadata type, use $(expr) to load the metadata into the elements

    30  * matched by expr, then redefine the metadata type and run another $(expr) for other elements.

    31  * 

    32  * @name $.metadata.setType

    33  *

    34  * @example <p id="one" class="some_class {item_id: 1, item_label: 'Label'}">This is a p</p>

    35  * @before $.metadata.setType("class")

    36  * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

    37  * @desc Reads metadata from the class attribute

    38  * 

    39  * @example <p id="one" class="some_class" data="{item_id: 1, item_label: 'Label'}">This is a p</p>

    40  * @before $.metadata.setType("attr", "data")

    41  * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

    42  * @desc Reads metadata from a "data" attribute

    43  * 

    44  * @example <p id="one" class="some_class"><script>{item_id: 1, item_label: 'Label'}</script>This is a p</p>

    45  * @before $.metadata.setType("elem", "script")

    46  * @after $("#one").metadata().item_id == 1; $("#one").metadata().item_label == "Label"

    47  * @desc Reads metadata from a nested script element

    48  * 

    49  * @param String type The encoding type

    50  * @param String name The name of the attribute to be used to get metadata (optional)

    51  * @cat Plugins/Metadata

    52  * @descr Sets the type of encoding to be used when loading metadata for the first time

    53  * @type undefined

    54  * @see metadata()

    55  */

    56 

    57 (function($) {

    58 

    59 $.extend({

    60 	metadata : {

    61 		defaults : {

    62 			type: 'class',

    63 			name: 'metadata',

    64 			cre: /({.*})/,

    65 			single: 'metadata'

    66 		},

    67 		setType: function( type, name ){

    68 			this.defaults.type = type;

    69 			this.defaults.name = name;

    70 		},

    71 		get: function( elem, opts ){

    72 			var settings = $.extend({},this.defaults,opts);

    73 			// check for empty string in single property

    74 			if ( !settings.single.length ) settings.single = 'metadata';

    75 			

    76 			var data = $.data(elem, settings.single);

    77 			// returned cached data if it already exists

    78 			if ( data ) return data;

    79 			

    80 			data = "{}";

    81 			

    82 			if ( settings.type == "class" ) {

    83 				var m = settings.cre.exec( elem.className );

    84 				if ( m )

    85 					data = m[1];

    86 			} else if ( settings.type == "elem" ) {

    87 				if( !elem.getElementsByTagName )

    88 					return undefined;

    89 				var e = elem.getElementsByTagName(settings.name);

    90 				if ( e.length )

    91 					data = $.trim(e[0].innerHTML);

    92 			} else if ( elem.getAttribute != undefined ) {

    93 				var attr = elem.getAttribute( settings.name );

    94 				if ( attr )

    95 					data = attr;

    96 			}

    97 			

    98 			if ( data.indexOf( '{' ) <0 )

    99 			data = "{" + data + "}";

   100 			

   101 			data = eval("(" + data + ")");

   102 			

   103 			$.data( elem, settings.single, data );

   104 			return data;

   105 		}

   106 	}

   107 });

   108 

   109 /**

   110  * Returns the metadata object for the first member of the jQuery object.

   111  *

   112  * @name metadata

   113  * @descr Returns element's metadata object

   114  * @param Object opts An object contianing settings to override the defaults

   115  * @type jQuery

   116  * @cat Plugins/Metadata

   117  */

   118 $.fn.metadata = function( opts ){

   119 	return $.metadata.get( this[0], opts );

   120 };

   121 

   122 })(jQuery);