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;