My module has some imagebuttons that show a sub-menu when clicked. The absolute position of the menu is calculated using javascript, as expected. This has worked well till now. But we are noticing a problem in DNN6. The menu position is off by a significant number of pixels (probably a couple hundred).
Since I did not write the calculation code, and neither am I a JS expert, I cannot understand how DNN6 is affecting it.
Here is the function:
function AbsolutePosition(obj) {
        var pos = null;
        if(obj != null) {
            pos = new Object();
            pos.top = obj.offsetTop;
            pos.left = obj.offsetLeft;
            pos.width = obj.offsetWidth;
            pos.height= obj.offsetHeight;
            obj = obj.offsetParent;
            while(obj != null) {
                pos.top += obj.offsetTop;
                pos.left += obj.offsetLeft;
                obj = obj.offsetParent;
            }
        }
return(pos);
}

I would like to understand how this code can be affected by the parent page structure - because changing the skin did not make any difference. This has something to do with how page elements are organized.
Any input appreciated! Thanks.