ASP中一個很不錯的四位元字驗證碼產生代碼 – [ASP程式]

<%
Call Com_CreatValidCode("ValidCode")

Sub Com_CreatValidCode(pSN)
' 禁止緩衝
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 = 4 ' 雜點出現的機率
Const cAmount = 10 ' 文字數量
Const cCode = "0123456789"

' 顏色的資料(字元，背景)
Dim vColorData(1)
vColorData(0) = ChrB(1) & ChrB(52) & ChrB(255)  ' 藍1，綠52，紅255（紅色）
vColorData(1) = ChrB(255) & ChrB(255) & ChrB(255) ' 藍255，綠255，紅255

' 隨機產生字元
Dim vCode(4), vCodes
For i = 0 To 3
  vCode(i) = Int(Rnd * cAmount)
  vCodes = vCodes & Mid(cCode, vCode(i) + 1, 1)
Next

'session("VCodes")=vCodes   '記錄入Session
session("CheckCode")=vCodes   '記錄入Session
' 字元的資料
Dim vNumberData(35)
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"
' 輸出影像檔頭
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)

' 輸出映像資訊頭
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  ' 曆經所有行
  For ii = 0 To 3  ' 曆經所有字
   For iii = 1 To 10 ' 曆經所有像素
    ' 逐行、逐字、逐像素地輸出映像資料
    If Rnd * 99 + 1 < cOdds Then ' 隨機產生雜點
     Response.BinaryWrite vColorData(0)
    Else
     Response.BinaryWrite vColorData(Mid(vNumberData(vCode(ii)), i * 10 + iii, 1))
    End If
   Next
  Next
Next

End Sub

'產生的驗證碼存在SESSION中，在需要引用的地方<img src="此頁面.asp">就會顯示出來

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