var isnn,isie

if(navigator.appName=='Microsoft Internet Explorer') //check the browser
{  isie=true }

if(navigator.appName=='Netscape')
{  isnn=true }


function key(e)   
{
	if(isie) {
		if(event.keyCode==17 || event.keyCode==18 || event.keyCode==93) {
			//alert("Sorry, you do not use ctrl+ key .") 
			return false;
		 } 
	}
	if(isnn){
	
		if (navigator.userAgent.indexOf('Firefox')==99){
		//evt = window.event;
		//alert(e.which);
		if(e.which==17 || e.which==18 || e.which==93) {
			alert("Sorry, you do not use ctrl+ key .") 
			return false;
		 }
		}
		}  
/*	if(isnn){
		if(event.keyCode==17 || event.keyCode==18 || event.keyCode==93) {
			alert("Sorry, you do not have permission to press this key.") 
			return false;
		 } 
		}  */ 

}

if (document.layers) window.captureEvents(Event.KEYPRESS);  
if (document.layers) window.captureEvents(Event.MOUSEDOWN);
if (document.layers) window.captureEvents(Event.MOUSEUP);
document.onkeydown=key;