function HideMenu() 
{
 var mX;
 var mY;
 var vDiv;
 var mDiv;
 var isvisible;
	if (isvisible == true)
{
		vDiv = document.all("menuDiv");
		mX = window.event.clientX + document.body.scrollLeft;
		mY = window.event.clientY + document.body.scrollTop;
		if ((mX < parseInt(vDiv.style.left)) || (mX > parseInt(vDiv.style.left)+vDiv.offsetWidth) || (mY < parseInt(vDiv.style.top)-h) || (mY > parseInt(vDiv.style.top)+vDiv.offsetHeight)){
			vDiv.style.visibility = "hidden";
			isvisible = false;
		}
}
}

<!--
 
if (window.Event) 
  document.captureEvents(Event.MOUSEUP); 
 
function nocontextmenu() 
{
 event.cancelBubble = true
 event.returnValue = false;
 
 return false;
}
 
function norightclick(e) 
{
 if (window.Event) 
 {
  if (e.which == 2 || e.which == 3)
   return false;
 }
 else
  if (event.button == 2 || event.button == 3)
  {
   event.cancelBubble = true
   event.returnValue = false;
   return false;
  }
 
}
 
document.oncontextmenu = nocontextmenu;  // for IE5+
document.onmousedown = norightclick; // JavaScript Document