Asp图片验证码

保存下面代码到code.asp,在需要显示验证码的地方使用
<img  src="code.asp"  alt="验证码"  />来显示,使用session("GetCode")
来提取验证码

<% 
Option  Explicit 
Response.buffer=true 
Call  Com_CreatValidCode("GetCode") 
Sub  Com_CreatValidCode(pSN) 
Response.Expires  =  -1 
Response.AddHeader  "Pragma","no-cache" 
Response.AddHeader  "cache-ctrol","no-cache" 
Response.ContentType  =  "Image/bmp" 
Randomize 
Dim  i,  ii,  iii 
Const  cOdds  =  6  '  杂点出现的机率 
Const  cAmount  =  10  '  文字数量 
Const  cCode  =  "0123456789abcd" 
'  颜色的数据(字符，背景) 
Dim  vColorData(1) 
vColorData(0)  =  ChrB(0)  &  ChrB(0)  &  ChrB(255)  '  蓝0，绿0，红0（黑色） 
vColorData(1)  =  ChrB(255)  &  ChrB(255)  &  ChrB(255)  '  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 
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