JavaScript - referencing 'this' in an inner function

Question

Consider the following code:

MyClass.prototype.my_func = function () {
    this.x = 10;
    $.ajax({
        // ...
        success: function (data) {
                   


        

Answer 1

The closure will have access to all objects defined in its parent's context. So if we have:

function() {
  var x = 10;
}

Then this is valid:

function() {
  var x = 10;

  (function() {
    alert(2*x); // 20
  }())
}

Therefore, when you define var _this = this you have merely defined a new variable in the parent's context that is available within the closure. See question #4371333 for more information on this "pattern."