Sys.Application.add_load(ApplicationLoad);
Sys.Application.add_init(ApplicationInit);

function ApplicationLoad(sender, args)
{
};

function ApplicationInit(sender)
{
    var prm = Sys.WebForms.PageRequestManager.getInstance();
    if (!prm.get_isInAsyncPostBack())
    {
        prm.add_initializeRequest(InitializeRequest);
        prm.add_endRequest(EndRequest);
    }
};

function InitializeRequest(sender, args)
{
    var progressBar = document.getElementById("progressBar");
    progressBar.style.display = "block";
};

function EndRequest(sender, args)
{
    var progressBar = document.getElementById("progressBar");
    progressBar.style.display = "none";
};