var prm = Sys.WebForms.PageRequestManager.getInstance();

prm.add_initializeRequest(initializeRequest);

prm.add_endRequest(endRequest);
var postbackElement;

function initializeRequest(sender, args) {
    document.body.style.cursor = "wait";
    if (prm.get_isInAsyncPostBack())
    {
        args.set_cancel(true);
    }
}
function endRequest(sender, args)
{
    document.body.style.cursor = "default";
}

function testScript(msg)
{
    alert(msg);
}