function addOnloadEvent(fnc){  
  if ( typeof window.addEventListener != "undefined" )  
    window.addEventListener( "load", fnc, false );  
  else if ( typeof window.attachEvent != "undefined" ) {  
    window.attachEvent( "onload", fnc );  
  }  
  else {  
    if ( window.onload != null ) {  
      var oldOnload = window.onload;  
      window.onload = function ( e ) {  
        oldOnload( e );  
        window[fnc]();  
      };  
    }  
    else  
      window.onload = fnc;  
  }  
}

addOnloadEvent(function() {setupZoom();});