1 <!DOCTYPE html>
2 <html lang="en">
3
4 <head>
5 <meta charset="UTF-8">
6 <meta http-equiv="X-UA-Compatible" content="IE=edge">
7 <meta name="viewport" content="width=device-width, initial-scale=1.0">
8 <title>Document</title>
9 </head>
10
11 <body>
12 <script>
13 'use strict';
14 window.onload = function() {
15 document.getElementById("btn").onclick = function() {
16 // 正则表达式
17 let regExp = /^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/;
18 let isOk = regExp.test(document.getElementById("email").value);
19 if (!isOk) {
20 document.getElementById("emailError").innerText = "邮箱格式不正确！";
21 }
22 }
23 document.getElementById("email").onfocus = function() {
24 document.getElementById("emailError").innerText = "";
25 }
26 }
27 </script>
28 <input type="text" name="" id="email">
29 <span id="emailError" style="color: red;"></span>
30 <br>
31 <input type="button" value="验证邮箱" id="btn">
32 </body>
33
34 </html>
