var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_pageLoaded(pageLoaded);
prm.add_beginRequest(beginRequest);

var postbackElement; 

function beginRequest(sender, args) 
{postbackElement = args.get_postBackElement();}

function pageLoaded(sender, args) {        
    if (typeof(postbackElement) == "undefined") {return;}
    var elements = getElementsByClassName("scroll_saver");            
    
    for (var i=0; i<elements.length; i++)
    {            
        elements[i].scrollTop = $get(elements[i].id + "_ScrollPos").value;
    }        
}

function getElementsByClassName(classname, node)  {
    if(!node) node = document.getElementsByTagName("body")[0];
    var a = [];
    var re = new RegExp('\\b' + classname + '\\b');
    var els = node.getElementsByTagName("*");
    for(var i=0,j=els.length; i<j; i++)
        if(re.test(els[i].className))a.push(els[i]);
    return a;
}