js表单提交的三种方式

第一种：

<script type="text/javascript">
    function check(form) {
        if (form.userId.value == ‘‘) {
            alert("请输入用户帐号!");
            form.userId.focus();
            return false;
        }
        if (form.password.value == ‘‘) {
            alert("请输入登录密码!");
            form.password.focus();
            return false;
        }
        return true;
    }
</script>  

<form action="login.do?act=login" method="post">
    用户帐号
    <input type=text name="userId" size="18" value="">
    <br>
    登录密码
    <input type="password" name="password" size="19" value=""/>
    <input type=submit name="submit1" value="登陆" onclick="return check(this.form)">
</form>  

第二种

<script type="text/javascript">
    function check(form) {
        if (form.userId.value == ‘‘) {
            alert("请输入用户帐号!");
            form.userId.focus();
            return false;
        }
        if (form.password.value == ‘‘) {
            alert("请输入登录密码!");
            form.password.focus();
            return false;
        }
        return true;
    }
</script>  

<form action="login.do?act=login" method="post" onsubmit="return check(this)">
    用户帐号
    <input type=text name="userId" size="18" value="">
    <br>
    登录密码
    <input type="password" name="password" size="19" value=""/>
    <input type=submit name="submit1" value="登陆">
</form> 

第三种

<script type="text/javascript">
    function check(form) {
        if (form.userId.value == ‘‘) {
            alert("请输入用户帐号!");
            form.userId.focus();
            return false;
        }
        if (form.password.value == ‘‘) {
            alert("请输入登录密码!");
            form.password.focus();
            return false;
        }
        document.myform.submit();
    }
</script>  

<form action="login.do?act=login" name="myform" method="post">
    用户帐号
    <input type=text name="userId" size="18" value="">
    <br>
    登录密码
    <input type="password" name="password" size="19" value=""/>
    <input type=button name="submit1" value="登陆" onclick="check(this.form)">
</form>