这个程序主要是先生成一个随机数，然后根据生成的随机数经过变换后作为XBM图片的内容，最后显示这个图片. 验证时中要获取输入的数字和Session("validatecode")比较，如果相等则通过验证（还要注意一下相比较的两数据的类型保持一致）。

如何显示生成的图片呢？ <img src="xbm.asp"></img>

关于XBM图的格式信息，看这里
http://www.zdnet.com.cn/developer/tech/story/0,2000081602,39134972,00.htm

xbm.asp的代码如下
<!--#include file="numcode.asp"--> <% '开启缓冲 Response.Buffer = True With Response .Expires = -1 .AddHeader "Pragma","no-cache" .AddHeader "cache-ctrol","no-cache" End With Dim num Randomize num = Int(7999 * Rnd + 2000) Session("validateCode") = num Dim Image Dim Width, Height Dim digtal Dim Length Dim sort Dim hc Length = 4 hc = chr(13) & chr(10) Redim sort(Length) digital = "" For I = 1 To Length - Len(num) digital = digital & "0" Next For I = 1 To Len(num) digital = digital & Mid(num, I, 1) Next For I = 1 To Len(digital) sort(I) = Mid(digital, I, 1) Next Width = 8 * Len(digital) Height = 10 Response.ContentType = "image/x-xbitmap" Image = "#define counter_width " & Width & hc Image = Image & "#define counter_height " & Height & hc Image = Image & "static unsigned char counter_bits[] = {" & hc For I = 1 To Height For J = 1 To Length Image = Image & a(sort(J),I) & "," Next Next Image = Left(Image, Len(Image) - 1) Image = Image & "};" & hc Response.Write Image %>
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Numcode.asp的代码如下：
<% Dim a(10,10) a(0,1) = "0x3c" '数字0 a(0,2) = "0x66" a(0,3) = "0xc3" a(0,4) = "0xc3" a(0,5) = "0xc3" a(0,6) = "0xc3" a(0,7) = "0xc3" a(0,8) = "0xc3" a(0,9) = "0x66" a(0,10)= "0x3c" a(1,1) = "0x18" '数字1 a(1,2) = "0x1c" a(1,3) = "0x18" a(1,4) = "0x18" a(1,5) = "0x18" a(1,6) = "0x18" a(1,7) = "0x18" a(1,8) = "0x18" a(1,9) = "0x18" a(0,10)= "0x7e" a(2,1) = "0x3c" '数字2 a(2,2) = "0x66" a(2,3) = "0x60" a(2,4) = "0x60" a(2,5) = "0x30" a(2,6) = "0x18" a(2,7) = "0x0c" a(2,8) = "0x06" a(2,9) = "0x06" a(2,10)= "0x7e" a(3,1) = "0x3c" '数字3 a(3,2) = "0x66" a(3,3) = "0xc0" a(3,4) = "0x60" a(3,5) = "0x1c" a(3,6) = "0x60" a(3,7) = "0xc0" a(3,8) = "0xc0" a(3,9) = "0x66" a(3,10)= "0x38" a(4,1) = "0x38" '数字4 a(4,2) = "0x3c" a(4,3) = "0x36" a(4,4) = "0x33" a(4,5) = "0x33" a(4,6) = "0x33" a(4,7) = "0xff" a(4,8) = "0x30" a(4,9) = "0x30" a(4,10)= "0xfe" a(5,1) = "0xfe" '数字5 a(5,2) = "0xfe" a(5,3) = "0x06" a(5,4) = "0x06" a(5,5) = "0x3e" a(5,6) = "0x60" a(5,7) = "0xc0" a(5,8) = "0xc3" a(5,9) = "0x66" a(5,10)= "0x3c" a(6,1) = "0x60" '数字6 a(6,2) = "0x30" a(6,3) = "0x18" a(6,4) = "0x0c" a(6,5) = "0x3e" a(6,6) = "0x63" a(6,7) = "0xc3" a(6,8) = "0xc3" a(6,9) = "0x66" a(6,10) ="0x3c" a(7,1) = "0xff" '数字7 a(7,2) = "0xc0" a(7,3) = "0x60" a(7,4) = "0x30" a(7,5) = "0x18" a(7,6) = "0x18" a(7,7) = "0x18" a(7,8) = "0x18" a(7,9) = "0x18" a(7,10)= "0x18" a(8,1) = "0x3c" '数字8 a(8,2) = "0x66" a(8,3) = "0xc3" a(8,4) = "0x66" a(8,5) = "0x3c" a(8,6) = "0x66" a(8,7) = "0xc3" a(8,8) = "0xc3" a(8,9) = "0x66" a(8,10)= "0x3c" a(9,1) = "0x3c" '数字9 a(9,2) = "0x66" a(9,3) = "0xc3" a(9,4) = "0xc3" a(9,5) = "0x66" a(9,6) = "0x3c" a(9,7) = "0x18" a(9,8) = "0x0c" a(9,9) = "0x06" a(9,10)= "0x03" %>
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