Scroller object not working in IE7 But Working in IE8

I am having difficulties trying to solve a runtime error that I get in IE7 but its working fine in IE8, it says that this.scroller is null or not an object for a scroller that I use, but what surprises me is that it is working on every browser. Please I need a solution. If I have not clarified my question please let me know. I am just look开发者_运维百科ing for a reason that may cause this.

have you tried checking pulling back scroller using getElementsbyID instead?

var elem = document.getElementById("scroller");
if (!elem)
{
   //do stuff
}