if(ns4)
  { 
   document.captureEvents(Event.MOUSEUP);
   document.captureEvents(Event.MOUSEDOWN);
  }
document.oncontextmenu=new Function("return false;");
document.onmouseup    = mouseUp;
document.onmouseClick = mouseDown;
function mouseUp(evt) {return;}
function mouseDown(evt) {return;}