function a(){
alert("fun a()");
}
function b(){
alert("fun b()");
}
var methodName = "";
//method1
methodName = "a";
function method1(methodName){
//Initialize the this.func property,
this.func = function(){};
try{
//Using the eval method, assign the method represented by the method name we passed in as an object to the func property of method1.
//If the methodName is not found, the eval method throws an exception
this.func = eval(methodName);
}catch(e){
alert(methodName+"() Does not exist! ");
}
}
var c = new m(methodName);
c.func();


methodName = "b";
function method2(methodName){
this.func = new Function(methodName+"();");
}
var c = new m(methodName);
try{
c.func();
}catch(e){
Ext.Msg.alert(methodName+"() Does not exist! ");
}