Maintaining Scroll Position on postback in an updatepanel

var scrollTop;
Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequestHandler);
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);

function BeginRequestHandler(sender, args) {
    var elem = document.getElementById('ScrollList');
    if (elem !== null) {
        scrollTop = elem.scrollTop;
    }
}

function EndRequestHandler(sender, args) {
    var elem = document.getElementById('ScrollList');
    if (elem !== null) {
        elem.scrollTop = scrollTop;
    }
}