Would it be something like this ?

 Sys.Application.add_init(appl_init);
 
   function appl_init()
{
    var pgRegMgr = Sys.WebForms.PageRequestManager.getInstance();
 
 pgRegMgr.add_endRequest(EndHandler);
}

   function EndHandler()
{           
     afterAsyncPostBack($(function(){$('#asd').toggle(1000);}););

}