Onclick javascript-Calling apex method

{!REQUIRESCRIPT("/soap/ajax/30.0/connection.js")}
{!REQUIRESCRIPT("/soap/ajax/30.0/apex.js")}
try{
	var eventId= '{!Event.Id}';
	var nurl="/"+eventId;  
	// Now make a synchronous call to the Apex Web service method 
	var result = sforce.apex.execute ( 
		"SendNotificationToAttendee", // class 
		"sendNotification", // method 
		{ eid: eventId } 
		); 
	alert("Notification sent succusfully"); 
	window.location.replace(nurl);

}catch(e){
	alert('some system error occured. Please try later');
}

//*************Apex Class******************
global class SendNotificationToAttendee{
    WebService static boolean sendNotification(Id eid){
        //write your logic here
        return true;
    }
}