<script>
    function validate()
    {
        if ($("input[id=customer.username]").val() == '')
        {
            alert('用户名错误');
            $("input[id=customer.username]").focus();
            return false;
        }
        if ($("input[id=customer.password]").val() == '')
        {
            alert('密码错误');
            $("input[id=customer.password]").focus();
            return false;
        }
        if (checkEmail($("input[id=customer.username]").val()))
        {
            alert('用户名错误');
            $("input[id=customer.username]").focus();
            return false;
        }
        return true;
    }
    function form_submit()
    {
        $("form[id='login_include']").submit();
    }
</script>

<table width="240" border="0" cellspacing="0" cellpadding="0">
<tr>
<td align="center" width="224" height="28">
<a href="javascript:form_submit();"class="shortButton">登陆</a>
</td>
<td width="16" height="28"></td>
</tr>
</table>

请问下，这段代码哪里错了，我运行是可以通过的，哪里需要修改呢？