js回车触发

<script language="javascript" type="text/javascript"> 

function KeyDown()
{
    if (event.keyCode == 13) //13表示按下回车
    {
        event.returnValue=false;
        event.cancel = true;
        admin_form.loginBtn.click();
    }
}

</script>

使用方法：
<form name="admin_form" method="">
用户名:<INPUT TYPE=text SIZE=20 maxlength = 8 onkeydown=KeyDown()>
密码:<INPUT TYPE=password SIZE=20 maxlength = 8 onkeydown=KeyDown()>
<input type="submit" name="loginBtn" value="提交" />
</form>