Scroll back to page start after Asyncronous postback(multiple update panels)

I have multiple update panels in User controls and it cause page to go to start after each asynchronous postback. By adding this code, I am able to handle the Problem I am facing.

the code in script tag is:
var xpos, ypos;

function windowScroll() {
xpos = document.body.parentNode.scrollLeft; //window.scrollX is not compatible with IE 6
ypos = document.body.parentNode.scrollTop; //window.scrollY is not compatible with IE 6
}
function pageLoaded(sender, args) {
window.scrollTo(xpos, ypos);
}

Sys.WebForms.PageRequestManager.getInstance().add_endRequest(pageLoaded);
window.onscroll = windowScroll;

Adding this code in body section in the end because 'Sys' must have to defined before using this code.