Function原生类型扩展

•Function.createDelegate(instance, method)方法：
–得到一个方法引用，执行它时则会调用method方法，并且保证method方法的上下文this引用为instance
•Function.createCallback(method, context)方法：
–得到一个方法引用，执行它时则会调用method方法，并将context作为额外的参数传入

aspx

     < form id = " form1 "  runat = " server " >
         < asp:ScriptManager ID = " ScriptManager1 "  runat = " server "   />
        
         < input type = " button "  value = " Click Me "  id = " btn "   />
        
         < script language = " javascript "  type = " text/javascript " >             
            var obj  =  
            {
                text :  " Hello " ,
                onClick : function(e, arg)
                {
                    alert( this .text  +   "   "   +  arg);
                }
            }
            
             //  obj.onClick();
             //  $addHandler($get("btn"), "click", obj.onClick);
             //  var onClickDelegate = Function.createDelegate(obj, obj.onClick);
            var onClickDelegate  =  Function.createCallback(
                Function.createDelegate(obj, obj.onClick),  " World " );
            $addHandler($ get ( " btn " ),  " click " , onClickDelegate);
         </ script >
     </ form >