var NN, IE;
function recognizeBrowser()
{
IE = false;
var str=navigator.userAgent;
IE = (str.indexOf('MSIE')!=-1)?true:false;
}

recognizeBrowser();
if (NN){
		document.captureEvents(Event.MOUSEDOWN);
		
		document.onkeydown=blockKeyDownNN;
		}
if (IE) {
		
		document.onkeydown=blockKeyDownIE;
		}
		
function blockKeyDownIE()
{if (event.keyCode==17){
			
			return false;
			}
}