不能手动输入或粘贴详解编程语言

function getOs(){ 
 	var OsObject = ""; 
 	if (navigator.userAgent.indexOf("MSIE") > 0) { 
 		return "MSIE"; 
 	} 
 	if (isFirefox = navigator.userAgent.indexOf("Firefox") > 0) { 
 		return "Firefox"; 
 	} 
 	if (isSafari = navigator.userAgent.indexOf("Safari") > 0) { 
 		return "Safari"; 
 	} 
 	if (isCamino = navigator.userAgent.indexOf("Camino") > 0) { 
 		return "Camino"; 
 	} 
 	if (isMozilla = navigator.userAgent.indexOf("Gecko/") > 0) { 
 		return "Gecko"; 
 	} 
 } 
 
 function forbid(){ 
		if(getOs() == 'MSIE'){ 
			if(event.keyCode!=46){if(event.preventDefault)event.preventDefault();else event.returnValue=false;} 
		} 
	}

:onkeydown => "forbid();", :oncontextmenu => 'forbid();'