Plugin for Notification of html5 with Chrome

Notification.js

/**
 *	Notification
 *	@author:	ijse
 *	@require:	Chrome10+
 *	@params:	Same as webkitNotifications.create[HTML]Notification()
 *	@usage:
 *		new Notify("http://www.baidu.com").onshow(function() {
 *				alert("show");
 *			}).onclose(function() {
 *				alert("close");
 *			}).show();
 */
window.Notify = function() {
	var _params = arguments;
	// Validate arguments
	if(_params.length == 0) {
		console.error("Notify need at least one argument");
		return ;
	}
	// Check browser support
	if(!window.webkitNotifications) {
		console.error("Your browser does not support webkitNotifications feature!!");
		return ;
	}

	var _onclose, _onclick, _onerror, _onshow;
	var _notification, _replaceId, _showFlag = false;

	function bindEvents() {
		// Add event listeners
		// In W3C, display event is called show
		_notification.addEventListener("display", _onshow, false);
		_notification.addEventListener("click", _onclick, false);
		_notification.addEventListener("error", _onerror, false);
		_notification.addEventListener("close", _onclose, false);
		
		if(_replaceId)
			_notification.replaceId = _replaceId;
		// !!IMPORTANT&&WEIRD!! remove next line no events will work
		var t = _notification;
	}
	function createfn(permission) {
		// About permission on Chrome:
		// 		PERMISSION_ALLOWED (0) indicates that the user has granted permission to scripts with this origin to show notifications.
		//		PERMISSION_NOT_ALLOWED (1) indicates that the user has not taken an action regarding notifications for scripts from this origin.
		//		PERMISSION_DENIED (2) indicates that the user has explicitly blocked scripts with this origin from showing notifications.
		if(permission == 0) {
			// If permission is allowed
			// Create notification
			if(_params.length == 1)
				_notification = window.webkitNotifications.createHTMLNotification(_params[0]);
			else
				_notification = window.webkitNotifications.createNotification(_params[0],_params[1],_params[2]);
			
			// Bind events
			bindEvents();

			// Show, if yes flag
			!!_showFlag && _notification.show();
		} else {
			if(_onerror)
				_onerror.call(this);
			console.error("Notification permission is denied!!");
		}
	}

	// If permission already allowed, do not require again
	if(window.webkitNotifications.checkPermission() != 0) {
		// Require permission from user
		window.webkitNotifications.requestPermission(function() {
			createfn.call(this, window.webkitNotifications.checkPermission());
		});
	} else {
		createfn.call(this, window.webkitNotifications.checkPermission());
	}

	// Return handler methods
	return {
		onclose: function(fn) { _onclose = fn; return this; },
		onclick: function(fn) { _onclick = fn; return this; },
		onerror: function(fn) { _onerror = fn; return this; },
		onshow : function(fn) { _onshow  = fn; return this; },

		show: function(replaceId) {
			_replaceId = replaceId;
			if(_notification) {
				// Notification already been created
				bindEvents();
				_notification.show();
			} else {
				// Flag yes to show
				_showFlag = true;
			}
			return _notification;
		},
		cancel: function() {
			_notification.cancel();
		}
	} // return handler
}