var isNS = (navigator.appName == "Netscape") ? 1 : 0;
if(navigator.appName == "Netscape") document.captureEvents(Event.MOUSEDOWN||Event.MOUSEUP);
  	
function mischandler()
{
   	return false;
}

function mousehandler(e)
{
 	var myevent = (isNS) ? e : event;
 	var eventbutton = (isNS) ? myevent.which : myevent.button;
	if((eventbutton==2)||(eventbutton==3)) return false;
}

document.oncontextmenu = mischandler; 	
document.onmousedown = mousehandler;
document.onmouseup = mousehandler;