var postbackElement;

if (window.document.all)
{
    window.attachEvent('onload', window_load);
}
else
{
    window.addEventListener('load', window_load, false);
}

function window_load(sender, args)
{
    var element = document.getElementById('hiddenPostbackControlId');

    if (element)
    {
        element.value = '';
    }
    
    Sys.WebForms.PageRequestManager.getInstance().add_pageLoaded(pageLoaded);
    //Sys.WebForms.PageRequestManager.getInstance().add_endRequest(pageLoaded);
    //Sys.WebForms.PageRequestManager.getInstance().add_pageLoading(pageLoaded);
    Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(beginRequest);
}

function beginRequest(sender, args)
{
    postbackElement = args.get_postBackElement();
    Sys.WebForms.PageRequestManager.getInstance()._scrollPosition = null;
}

function pageLoaded(sender, args)
{
    alert('Hi');
    if (typeof (postbackElement) === "undefined")
    {
        return;
    }

    //var id = document.getElementById('<%=hdnPostbackControlID.ClientID %>').value;
    var element = document.getElementById('hiddenPostbackControlId');

    //debugger;
    if (element)
    {
        /* Here we pass in the control's ID */
        if (element.value === '__REFRESH__')
        {
            alert('Hi2');
            window.scrollTo(0, 0);
        }
        else if (postbackElement.id === element.value)
        {
            window.scrollTo(0, 0);
            //return;
        }
        element.value = '';
    }
}