data.js

(function( jQuery ) {

var rbrace = /^(?:\{.*\}|\[.*\])$/,
	rmultiDash = /([a-z])([A-Z])/g;

jQuery.extend({
	cache: {},

	// Please use with caution
	uuid: 0,

	// Unique for each copy of jQuery on the page
	// Non-digits removed to match rinlinejQuery
	expando: "jQuery" + ( jQuery.fn.jquery + Math.random() ).replace( /\D/g, "" ),

	// 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
	},

	hasData: function( elem ) {
		elem = elem.nodeType ? jQuery.cache[ elem[jQuery.expando] ] : elem[ jQuery.expando ];

		return !!elem && !isEmptyDataObject( elem );
	},

	data: function( elem, name, data, pvt /* Internal Use Only */ ) {
		if ( !jQuery.acceptData( elem ) ) {
			return;
		}

		var internalKey = jQuery.expando, getByName = typeof name === "string", thisCache,

			// We have to handle DOM nodes and JS objects differently because IE6-7
			// can't GC object references properly across the DOM-JS boundary
			isNode = elem.nodeType,

			// Only DOM nodes need the global jQuery cache; JS object data is
			// attached directly to the object so GC can occur automatically
			cache = isNode ? jQuery.cache : elem,

			// Only defining an ID for JS objects if its cache already exists allows
			// the code to shortcut on the same path as a DOM node with no cache
			id = isNode ? elem[ jQuery.expando ] : elem[ jQuery.expando ] && jQuery.expando;

		// Avoid doing any more work than we need to when trying to get data on an
		// object that has no data at all
		if ( (!id || (pvt && id && !cache[ id ][ internalKey ])) && getByName && data === undefined ) {
			return;
		}

		if ( !id ) {
			// Only DOM nodes need a new unique ID for each element since their data
			// ends up in the global cache
			if ( isNode ) {
				elem[ jQuery.expando ] = id = ++jQuery.uuid;
			} else {
				id = jQuery.expando;
			}
		}

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

			// TODO: This is a hack for 1.5 ONLY. Avoids exposing jQuery
			// metadata on plain JS objects when the object is serialized using
			// JSON.stringify
			if ( !isNode ) {
				cache[ id ].toJSON = jQuery.noop;
			}
		}

		// An object can be passed to jQuery.data instead of a key/value pair; this gets
		// shallow copied over onto the existing cache
		if ( typeof name === "object" || typeof name === "function" ) {
			if ( pvt ) {
				cache[ id ][ internalKey ] = jQuery.extend(cache[ id ][ internalKey ], name);
			} else {
				cache[ id ] = jQuery.extend(cache[ id ], name);
			}
		}

		thisCache = cache[ id ];

		// Internal jQuery data is stored in a separate object inside the object's data
		// cache in order to avoid key collisions between internal data and user-defined
		// data
		if ( pvt ) {
			if ( !thisCache[ internalKey ] ) {
				thisCache[ internalKey ] = {};
			}

			thisCache = thisCache[ internalKey ];
		}

		if ( data !== undefined ) {
			thisCache[ jQuery.camelCase( name ) ] = data;
		}

		// TODO: This is a hack for 1.5 ONLY. It will be removed in 1.6. Users should
		// not attempt to inspect the internal events object using jQuery.data, as this
		// internal data object is undocumented and subject to change.
		if ( name === "events" && !thisCache[name] ) {
			return thisCache[ internalKey ] && thisCache[ internalKey ].events;
		}

		return getByName ? thisCache[ jQuery.camelCase( name ) ] : thisCache;
	},

	removeData: function( elem, name, pvt /* Internal Use Only */ ) {
		if ( !jQuery.acceptData( elem ) ) {
			return;
		}

		var internalKey = jQuery.expando, isNode = elem.nodeType,

			// See jQuery.data for more information
			cache = isNode ? jQuery.cache : elem,

			// See jQuery.data for more information
			id = isNode ? elem[ jQuery.expando ] : jQuery.expando;

		// If there is already no cache entry for this object, there is no
		// purpose in continuing
		if ( !cache[ id ] ) {
			return;
		}

		if ( name ) {
			var thisCache = pvt ? cache[ id ][ internalKey ] : cache[ id ];

			if ( thisCache ) {
				delete thisCache[ name ];

				// If there is no data left in the cache, we want to continue
				// and let the cache object itself get destroyed
				if ( !isEmptyDataObject(thisCache) ) {
					return;
				}
			}
		}

		// See jQuery.data for more information
		if ( pvt ) {
			delete cache[ id ][ internalKey ];

			// Don't destroy the parent cache unless the internal data object
			// had been the only thing left in it
			if ( !isEmptyDataObject(cache[ id ]) ) {
				return;
			}
		}

		var internalCache = cache[ id ][ internalKey ];

		// Browsers that fail expando deletion also refuse to delete expandos on
		// the window, but it will allow it on all other JS objects; other browsers
		// don't care
		if ( jQuery.support.deleteExpando || cache != window ) {
			delete cache[ id ];
		} else {
			cache[ id ] = null;
		}

		// We destroyed the entire user cache at once because it's faster than
		// iterating through each key, but we need to continue to persist internal
		// data if it existed
		if ( internalCache ) {
			cache[ id ] = {};
			// TODO: This is a hack for 1.5 ONLY. Avoids exposing jQuery
			// metadata on plain JS objects when the object is serialized using
			// JSON.stringify
			if ( !isNode ) {
				cache[ id ].toJSON = jQuery.noop;
			}

			cache[ id ][ internalKey ] = internalCache;

		// Otherwise, we need to eliminate the expando on the node to avoid
		// false lookups in the cache for entries that no longer exist
		} else if ( isNode ) {
			// IE does not allow us to delete expando properties from nodes,
			// nor does it have a removeAttribute function on Document nodes;
			// we must handle all of these cases
			if ( jQuery.support.deleteExpando ) {
				delete elem[ jQuery.expando ];
			} else if ( elem.removeAttribute ) {
				elem.removeAttribute( jQuery.expando );
			} else {
				elem[ jQuery.expando ] = null;
			}
		}
	},

	// For internal use only.
	_data: function( elem, name, data ) {
		return jQuery.data( elem, name, data, true );
	},

	// 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 ) {
		var data = null;

		if ( typeof key === "undefined" ) {
			if ( this.length ) {
				data = jQuery.data( this[0] );

				if ( this[0].nodeType === 1 ) {
			    var attr = this[0].attributes, name;
					for ( var i = 0, l = attr.length; i < l; i++ ) {
						name = attr[i].name;

						if ( name.indexOf( "data-" ) === 0 ) {
							name = jQuery.camelCase( name.substring(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 ) {
			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 ) {
		var name = "data-" + key.replace( rmultiDash, "$1-$2" ).toLowerCase();

		data = elem.getAttribute( name );

		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;
}

// TODO: This is a hack for 1.5 ONLY to allow objects with a single toJSON
// property to be considered empty objects; this property always exists in
// order to make sure JSON.stringify does not expose internal metadata
function isEmptyDataObject( obj ) {
	for ( var name in obj ) {
		if ( name !== "toJSON" ) {
			return false;
		}
	}

	return true;
}

})( jQuery );