网站验证码制作与调用

后台  一般处理程序生成验证码：

 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         }

View Code

前台   显示刷新 

html：

<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>

View Code

javascript:

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;

        }

View Code

利用Session["Code"] 存储对应的生成的code代码  便于登录的时候做判断

最终显示结果：