javascript 回车替换成TAB的脚本

<script type="text/javascript">
document.onkeydown=function enterToTab()
{
if(event.srcElement.type != 'submit' && event.srcElement.type!="image" && event.srcElement.type != 'textarea'
&& event.keyCode == 13)
event.keyCode = 9;
}
}
</script>