if(Sys){
    Sys.Application.add_load(ApplicationLoadHandlerProgress)
    Sys.Application.add_unload(ApplicationUnloadHandlerProgress)
}


function ApplicationLoadHandlerProgress(sender, args)
{
    var status = Sys.WebForms.PageRequestManager.getInstance().get_isInAsyncPostBack();
    if(status == false)
    {
        Sys.WebForms.PageRequestManager.getInstance().add_pageLoaded(page_OnLoad);
    }
}

function ApplicationUnloadHandlerProgress(sender, args)
{
    Sys.WebForms.PageRequestManager.getInstance().remove_pageLoaded(page_OnLoad);    
}
//declarar la funcion "page_OnLoad(sender, args)" que sera llamada luego
// de realisarce un request por ajax en un updatePanel
/*

function page_OnLoad(sender, args)
{
}

*/