Can any one help to add scrollbar with menu using java script?Infect i added all the code but its working in firefox and in any other browser but not in internet explorer

Here is the code i am using
function initScrollLayer() {
var navWin = document.getElementById('lnavwin');
if (navWin != null && navWin != 'undefined' )
{
if (navWin.addEventListener)
navWin.addEventListener('DOMMouseScroll', lmWheel, false);
var dataLayer = getLayerName(currentSection);
if (dataLayer!='lnav-data') document.getElementById('lnav-data').style.visibility='hidden';
var wndo = new dw_scrollObj('lnavwin', dataLayer);
wndo.bSizeDragBar = false;
document.getElementById('dragBar1').style.visibility='';
wndo.setUpScrollbar("dragBar1", "track1", "v", 1, 0);

dw_scrollObj.scrollTo('lnavwin', 0, scrollTo, 1);

}
}

you can also check the live page

http://www.zonetechsystems.com/terms.asp.

am waiting for response ..

thanks.