一、引用方法：<img src="yanzhengma.asp">
二、判断代码：
<%if trim(Server.HTMLEncode(Request.Form("yanzheng")))<>session("jd100_rn") then%>

三、将以下代码另存成yanzhengma.asp：

<%
Call Com_CreatValidCode("ValidCode")
Sub Com_CreatValidCode(pSN)
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 = 8 '杂点出现的机率  
Const cAmount = 10 '文字数量   
Const cCode = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" 
'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(235) & ChrB(235) & ChrB(235) '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("jd100_rn")=vCodes '记录入Session 

'字符的数据   
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"  
vNumberData(10) = "1111011111111101111111101011111110101111111010111111101011111100000111110111011111011101111000100011" 
  vNumberData(11) = "1000000111110111101111011110111101110111110000111111011101111101111011110111101111011110111000000111"  
vNumberData(12) = "1110000011110111101110111110111011111111101111111110111111111011111111101111101111011101111110001111" 
  vNumberData(13) = "1000001111110111011111011110111101111011110111101111011110111101111011110111101111011101111000001111" 
  vNumberData(14) = "1000000111110111101111011011111101101111110000111111011011111101101111110111111111011110111000000111" 
  vNumberData(15) = "1000000111110111101111011011111101101111110000111111011011111101101111110111111111011111111000111111" 
  vNumberData(16) = "1110000111110111011110111101111011111111101111111110111111111011100011101111011111011101111110001111"
   vNumberData(17) = "1000100011110111011111011101111101110111110000011111011101111101110111110111011111011101111000100011"
   vNumberData(18) = "1100000111111101111111110111111111011111111101111111110111111111011111111101111111110111111100000111" 
  vNumberData(19) = "1110000011111110111111111011111111101111111110111111111011111111101111111110111110111011111000011111" 
  vNumberData(20) = "1000100011110111011111011011111101011111110001111111010111111101101111110110111111011101111000100011" 
  vNumberData(21) = "1000111111110111111111011111111101111111110111111111011111111101111111110111111111011110111000000011" 
  vNumberData(22) = "1000100011110010011111001001111100100111110101011111010101111101010111110101011111010101111001010011" 
  vNumberData(23) = "1000100011110011011111001101111101010111110101011111010101111101100111110110011111011001111000110111"
   vNumberData(24) = "1110001111110111011110111110111011111011101111101110111110111011111011101111101111011101111110001111"  
vNumberData(25) = "1000000111110111101111011110111101111011110000011111011111111101111111110111111111011111111000111111"
   vNumberData(26) = "1110001111110111011110111110111011111011101111101110111110111011111011101001101111011001111110001011" 
  vNumberData(27) = "1000001111110111011111011101111101110111110000111111010111111101101111110110111111011101111000110011" 
  vNumberData(28) = "1110000011110111101111011110111101111111111001111111111001111111111011110111101111011110111100000111"
   vNumberData(29) = "1000000011101101101111110111111111011111111101111111110111111111011111111101111111110111111110001111"  
vNumberData(30) = "1000100011110111011111011101111101110111110111011111011101111101110111110111011111011101111110001111" 
  vNumberData(31) = "1000100011110111011111011101111101110111111010111111101011111110101111111010111111110111111111011111" 
  vNumberData(32) = "1001010011110101011111010101111101010111110101011111001001111110101111111010111111101011111110101111" 
  vNumberData(33) = "1000100011110111011111101011111110101111111101111111110111111110101111111010111111011101111000100011" 
  vNumberData(34) = "1000100011110111011111011101111110101111111010111111110111111111011111111101111111110111111110001111" 
  vNumberData(35) = "1100000011110111011111111101111111101111111110111111110111111111011111111011111111101110111100000011"  
'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%>