jquery/src/data.js

(function( jQuery ) {

var windowData = {},
	rbrace = /^(?:\{.*\}|\[.*\])$/;

jQuery.extend({
	cache: {},

	// Please use with caution
	uuid: 0,

	// Unique for each copy of jQuery on the page	
	expando: "jQuery" + jQuery.now(),

	// The following elements throw uncatchable exceptions if you
	// attempt to add expando properties to them.
	noData: {
		"embed": true,
		// Ban all objects except for Flash (which handle expandos)
		"object": "clsid:D27CDB6E-AE6D-11cf-96B8-444553540000",
		"applet": true
	},

	data: function( elem, name, data ) {
		if ( !jQuery.acceptData( elem ) ) {
			return;
		}

		elem = elem == window ?
			windowData :
			elem;

		var isNode = elem.nodeType,
			id = isNode ? elem[ jQuery.expando ] : null,
			cache = jQuery.cache, thisCache;

		if ( isNode && !id && typeof name === "string" && data === undefined ) {
			return;
		}

		// Get the data from the object directly
		if ( !isNode ) {
			cache = elem;

		// Compute a unique ID for the element
		} else if ( !id ) {
			elem[ jQuery.expando ] = id = ++jQuery.uuid;
		}

		// Avoid generating a new cache unless none exists and we
		// want to manipulate it.
		if ( typeof name === "object" ) {
			if ( isNode ) {
				cache[ id ] = jQuery.extend(cache[ id ], name);

			} else {
				jQuery.extend( cache, name );
			}

		} else if ( isNode && !cache[ id ] ) {
			cache[ id ] = {};
		}

		thisCache = isNode ? cache[ id ] : cache;

		// Prevent overriding the named cache with undefined values
		if ( data !== undefined ) {
			thisCache[ name ] = data;
		}

		return typeof name === "string" ? thisCache[ name ] : thisCache;
	},

	removeData: function( elem, name ) {
		if ( !jQuery.acceptData( elem ) ) {
			return;
		}

		elem = elem == window ?
			windowData :
			elem;

		var isNode = elem.nodeType,
			id = isNode ? elem[ jQuery.expando ] : elem,
			cache = jQuery.cache,
			thisCache = isNode ? cache[ id ] : id;

		// If we want to remove a specific section of the element's data
		if ( name ) {
			if ( thisCache ) {
				// Remove the section of cache data
				delete thisCache[ name ];

				// If we've removed all the data, remove the element's cache
				if ( isNode && jQuery.isEmptyObject(thisCache) ) {
					jQuery.removeData( elem );
				}
			}

		// Otherwise, we want to remove all of the element's data
		} else {
			if ( isNode && jQuery.support.deleteExpando ) {
				delete elem[ jQuery.expando ];

			} else if ( elem.removeAttribute ) {
				elem.removeAttribute( jQuery.expando );

			// Completely remove the data cache
			} else if ( isNode ) {
				delete cache[ id ];

			// Remove all fields from the object
			} else {
				for ( var n in elem ) {
					delete elem[ n ];
				}
			}
		}
	},

	// A method for determining if a DOM node can handle the data expando
	acceptData: function( elem ) {
		if ( elem.nodeName ) {
			var match = jQuery.noData[ elem.nodeName.toLowerCase() ];

			if ( match ) {
				return !(match === true || elem.getAttribute("classid") !== match);
			}
		}

		return true;
	}
});

jQuery.fn.extend({
	data: function( key, value ) {
		if ( typeof key === "undefined" ) {
			var data = null;

			if ( this.length ) {
				var attr = this[0].attributes, name;
				data = jQuery.data( this[0] );

				for ( var i = 0, l = attr.length; i < l; i++ ) {
					name = attr[i].name;

					if ( name.indexOf( "data-" ) === 0 ) {
						name = name.substr( 5 );
						dataAttr( this[0], name, data[ name ] );
					}
				}
			}

			return data;

		} else if ( typeof key === "object" ) {
			return this.each(function() {
				jQuery.data( this, key );
			});
		}

		var parts = key.split(".");
		parts[1] = parts[1] ? "." + parts[1] : "";

		if ( value === undefined ) {
			var data = this.triggerHandler("getData" + parts[1] + "!", [parts[0]]);

			// Try to fetch any internally stored data first
			if ( data === undefined && this.length ) {
				data = jQuery.data( this[0], key );
				data = dataAttr( this[0], key, data );
			}

			return data === undefined && parts[1] ?
				this.data( parts[0] ) :
				data;

		} else {
			return this.each(function() {
				var $this = jQuery( this ), args = [ parts[0], value ];

				$this.triggerHandler( "setData" + parts[1] + "!", args );
				jQuery.data( this, key, value );
				$this.triggerHandler( "changeData" + parts[1] + "!", args );
			});
		}
	},

	removeData: function( key ) {
		return this.each(function() {
			jQuery.removeData( this, key );
		});
	}
});

function dataAttr( elem, key, data ) {
	// If nothing was found internally, try to fetch any
	// data from the HTML5 data-* attribute
	if ( data === undefined && elem.nodeType === 1 ) {
		data = elem.getAttribute( "data-" + key );

		if ( typeof data === "string" ) {
			try {
				data = data === "true" ? true :
				data === "false" ? false :
				data === "null" ? null :
				!jQuery.isNaN( data ) ? parseFloat( data ) :
					rbrace.test( data ) ? jQuery.parseJSON( data ) :
					data;
			} catch( e ) {}

			// Make sure we set the data so it isn't changed later
			jQuery.data( elem, key, data );

		} else {
			data = undefined;
		}
	}

	return data;
}

})( jQuery );