如何在验证通过时执行javascript警报 [英] How to do javascript alert only when validation passes

问题描述

我有一个电子邮件文本框（必填字段）和一个按钮。我希望每当用户输入他的邮件ID并点击按钮时，就会出现一个JavaScript弹出窗口。



我的问题是当我点击按钮时，弹出窗口出现之前必填字段消息



我希望编写的JavaScript代码如果文本框为空则会显示请输入电子邮件ID验证消息，如果用户提供他的电子邮件ID，然后弹出窗口将出现;否则没有。



请帮帮我





这是我的文本框和按钮

I have an email textbox (required field) and a button. I want that whenever a user puts his mail id and clicks the button a JavaScript popup should appear.

My problem is when I click the button, that popup is appearing before the required-field msg.

I want JavaScript code written in a way that if textbox is empty then it will show a "please enter email id" validation message and if user gives his email id then that popup will appear; otherwise not.

pls help me out


this is my text box and button

<div class="input-append">
              <input type="email" id="email" name="email" placeholder="Your Email" required>
              <button class="subscribe-button btn" type="submit" onclick="myFunction()">SUBSCRIBE</button>
            </div>

这是我的javascript代码< br $> b $ b

and this is my javascript code

<script type="text/javascript">
function myFunction() {
    alert("You have done it");
}
</script>

推荐答案

这个例子怎么样



http://www.w3schools.com/js/tryit.asp?filename=tryjs_form_validation [ ^ ]

What about this example

http://www.w3schools.com/js/tryit.asp?filename=tryjs_form_validation[^]

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