用javascript实现用户登录验证

<script language=javascript>
function checkSubmit()
{
    if ((document.form1.name.value)=="")
    {
        window.alert ('姓名必须填写');
        document.form1.name.select();
        document.form1.name.focus();
        return false;
    }
    else
        return true;
}
</script>
<form name=”form1″ onsubmit=”javascript:return checkSubmit()”>
<input type=”text” name=”name”>
</form>