标签：
1 <!DOCTYPE html>
2 <html>
3 <head lang="en">
4 <meta charset="UTF-8">
5 <title></title>
6 <style>
7 div {
8 margin-bottom: 20px;
9 }
10
11 fieldset {
12 width: 300px;
13 }
14 </style>
15 </head>
16 <body>
17 <fieldset>
18 <legend>用户登录</legend>
19 <form action="" method="">
20 <div><label for="name">用户名</label>
21 <input type="text" id="name"><br>
22 </div>
23 <div><label for="pass">密 码</label>
24 <input type="text" id="pass">
25 </div>
26 <input type="submit" value="登录" id="login"
27 style="display: block;
28 margin-left:100px">
29 </form>
30 </fieldset>
31 <script type="text/javascript">
32 function $$(id) {
33 return document.getElementById(id);
34 }
35 function check() {
36 var $n = $$("name");
37 var $p = $$("pass");
38 if ($n.value == "") {
39 alert("请输入用户名!");
40 $n.focus();
41 return false;
42 }
43 if ($p.value == "") {
44 alert("请输入密码!");
45 $p.focus();
46 return false;
47 }
48 }
49 $$("login").onclick = function () {
50 return check();
51 }
52 </script>
53 </body>
54 </html>
标签：
原文地址：http://www.cnblogs.com/zfj-world/p/4771396.html
