转：asp随机数字验证码 生成BMP图 不需要补丁

验证码文件GetCode.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
%>

引用为图片<img src="GetCode.asp">
判断：
Code = bad(Request.Form("FM_Code"))
'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
echo alertInfo("校验码输入有误！",-1,2)
Response.End()
End If