如何使用Javascript验证我的Texbox [英] How Do I Validate My Texbox Using Javascript

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HTML

 <  < span class =code-leadattribute> div     class   =  input-append >  
 <  输入    type   =  email    id   =  email   名称  = 电子邮件   占位符  = 您的电子邮件  /  >  
 <  按钮    class   =  subscribe-button btn    type   =  submit    onclick   =  myFunction（） >  SUBSCRIBE <   / button  >  
 <   / div  >  

这是我的javascript

 <   script     type   =  text / javascript >  
函数myFunction（）{
 alert（你已经完成了）; 
} 
 <   / script  >  

解决方案

你需要写这样的东西：

 function myFunction（）{
  var  enteredEmail = document.getElementById（'  email'）。 value ; 
  if （enteredEmail ==  ）{
 alert（ 请输入电子邮件ID）; 
} 
  else  {
 alert（ 你已经完成了）; 
} 
} 

有很多教程可供谷歌使用。

请参阅此链接：电子邮件地址验证使用正则表达式的JavaScript

只需调用以下方法

 function checkEmail（）{
 
  var  email = document.getElementById（'  txtEmail ）; 
  var  filter = /^([a-zA-Z0-9_\.\-])+\@(([a-azA -Z0-9 \  - ]）+ \。）+（[a-zA-Z0-9] { 2 ， 4 }）+ 

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 HTML

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

and this is my javascript

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

解决方案

You need to write something like this:

function myFunction() {
       var enteredEmail = document.getElementById('email').value;
       if (enteredEmail == "") {
           alert("Please enter email id");
       }
       else {
           alert("You have done it");
       }
   }

There are a lot of tutorials available just google for it.

Refer this link : Email Address Validation in JavaScript using Regular Expressions

Just call the below method

function checkEmail() {

    var email = document.getElementById('txtEmail');
    var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+

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