网站验证码制作与调用

 1 public void ProcessRequest(HttpContext context)
 2         {
 3             int codeW = 80;
 4             int codeH = 22;
 5             int fontSize = 16;
 6             string chkCode = string.Empty;
 7             //颜色列表，用于验证码、噪线、噪点 
 8             Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };
 9             //字体列表，用于验证码 
10             string[] font = { "Times New Roman", "Verdana", "Arial", "Gungsuh", "Impact" };
11             //验证码的字符集，去掉了一些容易混淆的字符 
12             char[] character = { ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘8‘, ‘9‘, ‘a‘, ‘b‘, ‘d‘, ‘e‘, ‘f‘, ‘h‘, ‘k‘, ‘m‘, ‘n‘, ‘r‘, ‘x‘, ‘y‘, ‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘, ‘F‘, ‘G‘, ‘H‘, ‘J‘, ‘K‘, ‘L‘, ‘M‘, ‘N‘, ‘P‘, ‘R‘, ‘S‘, ‘T‘, ‘W‘, ‘X‘, ‘Y‘ };
13             Random rnd = new Random();
14             //生成验证码字符串 
15             for (int i = 0; i < 4; i++)
16             {
17                 chkCode += character[rnd.Next(character.Length)];
18             }
19             //写入Session
20             context.Session["Code"] = chkCode;
21             //创建画布
22             Bitmap bmp = new Bitmap(codeW, codeH);
23             Graphics g = Graphics.FromImage(bmp);
24             g.Clear(Color.White);
25             //画噪线 
26             for (int i = 0; i < 1; i++)
27             {
28                 int x1 = rnd.Next(codeW);
29                 int y1 = rnd.Next(codeH);
30                 int x2 = rnd.Next(codeW);
31                 int y2 = rnd.Next(codeH);
32                 Color clr = color[rnd.Next(color.Length)];
33                 g.DrawLine(new Pen(clr), x1, y1, x2, y2);
34             }
35             //画验证码字符串 
36             for (int i = 0; i < chkCode.Length; i++)
37             {
38                 string fnt = font[rnd.Next(font.Length)];
39                 Font ft = new Font(fnt, fontSize);
40                 Color clr = color[rnd.Next(color.Length)];
41                 g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 18 + 2, (float)0);
42             }
43             //画噪点 
44             for (int i = 0; i < 100; i++)
45             {
46                 int x = rnd.Next(bmp.Width);
47                 int y = rnd.Next(bmp.Height);
48                 Color clr = color[rnd.Next(color.Length)];
49                 bmp.SetPixel(x, y, clr);
50             }
51             //清除该页输出缓存，设置该页无缓存 
52             context.Response.Buffer = true;
53             context.Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
54             context.Response.Expires = 0;
55             context.Response.CacheControl = "no-cache";
56             context.Response.AppendHeader("Pragma", "No-Cache");
57             //将验证码图片写入内存流，并将其以 "image/Png" 格式输出 
58             MemoryStream ms = new MemoryStream();
59             try
60             {
61                 bmp.Save(ms, ImageFormat.Png);
62                 context.Response.ClearContent();
63                 context.Response.ContentType = "image/Png";
64                 context.Response.BinaryWrite(ms.ToArray());
65             }
66             finally
67             {
68                 //显式释放资源 
69                 bmp.Dispose();
70                 g.Dispose();
71             }
72         }

<img id="codeImg" alt="刷新验证码！" style="margin-bottom: -8px; cursor: pointer;" src="/Core/VerifyCode.ashx">
<a href="#" onclick="return getVerifyCode();">看不清？</a>

function getVerifyCode() {
            $(‘#codeImg‘).attr("src", "/Core/VerifyCode.ashx?d=" + generateMixed(10));
            return false;
        }

        var chars = [‘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‘];

        function generateMixed(n) {
            var res = "";
            for (var i = 0; i < n; i++) {
                var id = Math.ceil(Math.random() * 35);
                res += chars[id];
            }
            return res;
        }