1 <!DOCTYPE html>
2 <html lang="en">
3 <head>
4 <meta charset="UTF-8">
5 <title>Title</title>
6 </head>
7 <body>
8 <form action="" id="Form">
9 用户名：<input type="text" name="username" class="con" mark="用户名"><br>
10 密码 ：<input type="password" name="pwd" class="con" mark="密码"><br>
11 <input type="submit" value="submit">
12
13
14 </form>
15
16 <script src="jquery-3.2.1.js"></script>
17 <script>
18 $("#Form :submit").click(function () {
19 var flag=true;
20 $("#Form .con").each(function () {
21 if ($(this).val().trim().length==0){
22 var span=$("<span>");
23 var mark=$(this).attr("mark");
24 span.text(mark+"不能为空");
25
26 $(this).after(span);
27 flag=false;
28 return false;
29 };
30
31 });
32 return flag
33 });
34 </script>
35 </body>
36 </html>
