Question

I have a Javascript object that registers for the mouse move event. But my problem is that the event parameter is not being passed in my custom function, its always undefined.

If you look inside the function touchMove() below you will see that the parameter event is always undefined for some reason?

What am I doing wrong?

MyObject.prototype.registerPointerEvents = function()  
{
  var instance = this;  // function() { instance.func(); }
  var ele      = this.getAttrib("divEle");

  ele.addEventListener("mousemove", function() { instance.touchMove(); }, false); 
}

MyObject.prototype.touchMove = function( /*Event*/ event )
{
  // Virtual function to be overridden in child classes

  console.log("MOVE 1: "+event); // here it outputs event is undefined
  if (!event)
     event = window.event;

  console.log("MOVE 2: "+event); // here event is still undefined
  if (this.getAttrib("isDragging") == "true")
  {
     console.log("MOVE TRUE");
     this.getAttrib("divEle").style.left = event.clientX+"px";
     this.getAttrib("divEle").style.top  = event.clientY+"px";
  }
}

Answer 1

Of course is undefined, you are calling an anonymous function without the parameter.

Better use this:

ele.addEventListener("mousemove", instance.touchMove, false);

That is (almost) the same as

ele.addEventListener("mousemove", function(e) { instance.touchMove(e); }, false);