Javascript事件热键兼容ie|firefox

<textarea onkeydown="keyHanlder(event)"> 
</textarea> 
<script> 
function keyHanlder(e){ 
if(e.ctrlKey&&e.keyCode==13){ 
alert('"Ctrl+Enter"'); 
if(e.preventDefault)e.preventDefault(); 
else e.returnValue=false; 
} 
} 
</script>

<SCRIPT LANGUAGE="JavaScript"> 
<!-- 
function hotkey(e) 
{ 
//判断浏览器 
var ex = navigator.appName; 
var a = ex=='Microsoft Internet Explorer'? window.event.keyCode : e.which; 
alert(a); 
switch(a){ 
case 83: 
window.open('Myhomepage/search.htm','show') 
break; 
case 70: 
window.open('Myhomepage/favorite.htm','show') 
break; 
} 
}// end hotkey 
document.onkeydown = hotkey; //当onkeydown 事件发生时调用hotkey函数 
//--> 
</SCRIPT>