javascript 获取焦距触发按钮事件

<script type="text/javascript">

document.onkeydown=function(e)
{
e=e?e:window.event;
var keyCode=e.which?e.which:e.keyCode;
if(keyCode==13)
{
if(document.getElementById("tbxName").value == "")
{
document.getElementById("tbxName").focus();
}
else if(document.getElementById("tbxPassword").value == "")
{
document.getElementById("tbxPassword").focus();
}
else
{
document.getElementById("Button1").focus();
document.getElementById("Button1").click();
}
return false;

}
}

</script>