1 <!DOCTYPE html>
2 <html lang="en">
3 <head>
4 <meta charset="UTF-8">
5 <title>Title</title>
6 <style type="text/css">
7 *{
8 margin:0;
9 padding:0;
10 }
11 span{
12
13 height: 20px;
14 line-height: 20px;
15 text-align: center;
16 background: gray;
17 color: #f0f0f0;
18 }
19 div{
20 width:100px;
21 height: 100px;
22 border:1px solid red;
23 }
24 </style>
25 <script type="text/javascript">
26 window.onload = function () {
27 //随机生成四位数字的验证码
28 var t = parseInt(Math.random()*8999+1000);
29 var spanNode = document.getElementsByTagName("span")[0];
30 spanNode.innerHTML = t;
31 //随机生成含有字母的验证码
32 //注意toString括号里的值，可以不写，不写默认的是10，小于10只会出现数字。大于10会出现字母
33 var b = Math.random().toString(36).substr(2);
34 var span1Node = document.getElementsByTagName("span")[1];
35 span1Node.innerHTML =b;
36 //利用随机函数使颜色随机变化
37 var r =Math.round(Math.random()*256)%255;
38 var g =Math.round(Math.random()*256)%255;
39 var b =Math.round(Math.random()*256)%255;
40 var rgbB = "rgb("+r+","+b +","+g+")";
41 document.body.style.background =rgbB;
42 }
43 //随机产生数组里包含的验证码
44 //randomFlag表示是否随机
45 //min随机字符的最小长度
46 //max随机字符的最大长度
47 function randomWord(randomFlag, min, max){
48 var str = "",
49 range = min,
50 arr = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'];
51 // 随机产生
52 if(randomFlag){
53 range = Math.round(Math.random() * (max-min)) + min;
54 }
55 for(var i=0; i<range; i++){
56 pos = Math.round(Math.random() * (arr.length-1));
57 str += arr[pos];
58 }
59 return str;
60 }
61 var g = randomWord(true, 3, 8);
62 document.write(g);
63 </script>
64 </head>
65 <body>
66 <form action="">
67 <h3>产生四位数字的随机验证码</h3>
68 <span></span>
69 <input type="submit" value="换一组">
70 <h3>产生包含字母的随机验证码</h3>
71 <span></span>
72 <input type="submit" value="换一组">
73 </form>
74 </body>
75 </html>
