In AJAX how to retrive variable from inside of onreadystatechange = function () [duplicate]

Answer 1

Why not change MyVariable's scope to outside of the function?

var MyVariable;    
function ajaxFunction(){
    //creating AJAX 
     ...
    // Create a function that will receive data sent from the server
    ajaxRequest.onreadystatechange = function (){
        if(ajaxRequest.readyState == 4){
            //success code
            ======>Here i want to set variable <=====
            MyVariable='MyContent';
        }
    }
    //Retrieving page
     ....
}

function popup(){
    ajaxFunction();
    alert(MyVariable);
}