JS阻止form表单提交

当做登陆页面时，JS判断用户名密码为空时需要阻止form表单提交。

<script type="text/javascript">
    var a = true;
    function validate(){
        var username = document.getElementById("username").value;
        var password = document.getElementById("password").value;
        if(username==""||password==""){
            alert("Can't be empty");
            a= false;
             return;
        }else{
            a=true;
        }
    }
    function checkinput(){
        return a;
    }
</script>

<body>

    <form method="post" action="hello.do" onsubmit="return checkinput();"> 
    Username:
    <input type="text" name="username" id="username"><br><br>
    Password:
    <input type="password" name="password" id="password"><br><br>
    <center>
        <input type="submit" value="Login" name="login" onclick="validate()">
    </center>
</form>
        
</body>

点击submit后验证为空，form里的onsubmit获取到为false时就停止提交。

posted on 2017-01-22 15:14 lonske 阅读(1503) 评论(0) 编辑收藏举报