Jquery 侦听键盘事件并获取当前焦点控件ID

<script type="text/javascript">
$(document).ready(function(){
$(document).keydown(function(event){
if(event.keyCode==13){
var id=$("input:focus").attr("id");
switch(id){
case "keyword":
SearchFunction();
break;
case "...":
AnyFunction();
break;
}
}
});
});
</script> <input type="text" id="a1" /><input type="button" value="A" /><br />
<input type="text" id="a2" />