Question

I want the AJAX callback to trigger the alert() in myFucntion with “It worked” do how can I refer to the myobject object as this in ajaxResponse?

function myobject() {
    this.val = "worked";

    http.onreadystatechange = function ajaxResponse() {
        if (http.readyState == 4) {
            this.myFunction();
        }

        http.send(null);  
    }

    myobject.prototype.myFunction = function() {
    alert("it "+this.val);
}

Answer 1

ajaxResponse is a function in parent function, it’s called closure in javascript. When a closure uses a variable which is defined in its parent function, this variable can not be destroyed from memory, while the father function finishes execution.
So, define a temporary variable like this:

var objTmp = this;

Then you can use this variable objTmp in ajaxResponse.
Or you can do it like this:

http.onreadystatechange = (function(objTmp){
                         return 
                             function ajaxResponse{alert(objTmp.value)}
                       })(this)