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;