Event Handler Called With Wrong Context

In the SomeObj object, the onkeydown event handler this.doSomething is called in the wrong context (that of the textbox element) but it needs to be called in the context of this. H

Solution 1:

Copy the reference to a local variable, so that you can use it in a closure:

registerEvent: function() {
  var t = this;
  this.textboxElem.onkeydown = function() {
    t.doSomething();
  };
},