Back to Top Scroll Up

The following Javascript will go to top of the page, when the link is clicked.
// JavaScript Document

var up_timer

function getPosition(){
yoko = document.body.scrollLeft || document.documentElement.scrollLeft;
tate = document.body.scrollTop  || document.documentElement.scrollTop;

}

function pageup(x,y){
if(up_timer) clearTimeout(up_timer);
if(y >= 1){
getPosition();
var divisionY = (tate-(tate/5));
var Y = Math.floor(divisionY);
window.scrollTo(yoko,Y);
up_timer = setTimeout("pageup("+yoko+","+Y+")",2);
}else{
window.scrollTo(yoko,0);
clearTimeout(up_timer);
}
}

function scrollup(){
getPosition();
pageup(yoko,tate)
}