var aThumb = document.getElementById("thumb");
var scrolldiv=document.getElementById("scrollcontent");
Drag.init(aThumb, null, 0, 0, 0, 360); // 500
aThumb.onDrag = function(x, y) {

fixer = (scrolldiv.offsetHeight / 400) * -1; //600


scrolldiv.style.top=y * fixer +"px";
}