ASP验证码示例代码

调用代码：
<img src="yan.asp" alt="请点击刷新验证码" height="10" style="cursor : pointer;" onClick="this.src='yan.asp?t='+(new Date().getTime());" />

yan.asp

<%

Option Explicit

Response.buffer=true

Call Com_CreatValidCode("GetCode")

Sub Com_CreatValidCode(pSN)

' 禁止缓存

Response.Expires = -9999

Response.AddHeader "Pragma","no-cache"

Response.AddHeader "cache-ctrol","no-cache"

Response.ContentType = "Image/BMP"

Randomize

Dim i, ii, iii

Const cOdds = 2 ' 杂点出现的机率

Const cAmount = 10 ' 文字数量

Const cCode = "0123456789"

' 颜色的数据(字符，背景)

Dim vColorData(1)

vColorData(0) = ChrB(0) & ChrB(0) & ChrB(211)  ' 蓝0，绿0，红0（黑色）

vColorData(1) = ChrB(230) & ChrB(230) & ChrB(230) ' 蓝250，绿236，红211（浅蓝色）

' 随机产生字符

Dim vCode(4), vCodes

For i = 0 To 3

vCode(i) = Int(Rnd * cAmount)

vCodes = vCodes & Mid(cCode, vCode(i) + 1, 1)

Next

Session("pSN") = vCodes  '记录入Session

' 字符的数据

Dim vNumberData(9)

vNumberData(0) = "1110000111110111101111011110111101001011110100101111010010111101001011110111101111011110111110000111"

vNumberData(1) = "1111011111110001111111110111111111011111111101111111110111111111011111111101111111110111111100000111"

vNumberData(2) = "1110000111110111101111011110111111111011111111011111111011111111011111111011111111011110111100000011"

vNumberData(3) = "1110000111110111101111011110111111110111111100111111111101111111111011110111101111011110111110000111"

vNumberData(4) = "1111101111111110111111110011111110101111110110111111011011111100000011111110111111111011111111000011"

vNumberData(5) = "1100000011110111111111011111111101000111110011101111111110111111111011110111101111011110111110000111"

vNumberData(6) = "1111000111111011101111011111111101111111110100011111001110111101111011110111101111011110111110000111"

vNumberData(7) = "1100000011110111011111011101111111101111111110111111110111111111011111111101111111110111111111011111"

vNumberData(8) = "1110000111110111101111011110111101111011111000011111101101111101111011110111101111011110111110000111"

vNumberData(9) = "1110001111110111011111011110111101111011110111001111100010111111111011111111101111011101111110001111"

' 输出图像文件头

Response.BinaryWrite ChrB(66) & ChrB(77) & ChrB(230) & ChrB(4) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) &_

ChrB(0) & ChrB(0) & ChrB(54) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(40) & ChrB(0) &_

ChrB(0) & ChrB(0) & ChrB(40) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(10) & ChrB(0) &_

ChrB(0) & ChrB(0) & ChrB(1) & ChrB(0)

' 输出图像信息头

Response.BinaryWrite ChrB(24) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(176) & ChrB(4) &_

ChrB(0) & ChrB(0) & ChrB(18) & ChrB(11) & ChrB(0) & ChrB(0) & ChrB(18) & ChrB(11) &_

ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) & ChrB(0) &_

ChrB(0) & ChrB(0)

For i = 9 To 0 Step -1  ' 历经所有行

For ii = 0 To 3  ' 历经所有字

For iii = 1 To 10 ' 历经所有像素

' 逐行、逐字、逐像素地输出图像数据

If Rnd * 99 + 1 < cOdds Then ' 随机生成杂点

Response.BinaryWrite vColorData(0)

Else

Response.BinaryWrite vColorData(Mid(vNumberData(vCode(ii)), i * 10 + iii, 1))

End If

Next

Next

Next

End Sub

%>

验证

<% Code = Request.Form("ss")

'得到输入的验证码

If Code <> Session("pSN") Then

'判断输入的验证是否与图片显示的验证码一样

Response.Write("校验码输入有误！")

%>

<a href="index.asp#1">返回</a>

<%  Response.End()

End If %>