This program mainly generates a random number first, then transforms it according to the generated random number as the content of the XBM picture, and finally displays the picture. During verification, the input number is obtained and compared with Session ("validatecode"). If they are equal, Pass verification (also note that the types of the two compared data are consistent).
How to display the generated image? <img src="xbm.asp"></img>
For information on the format of XBM graphs, see here
http://www.zdnet.com.cn/developer/tech/story/0,2000081602,39134972,00.htm
The code of xbm.asp is as follows:
<!--#include file="numcode.asp"-->
<%
'Turn on buffering
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 digital
Dim Length
Dim sort
htK
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
%>
The code of Numcode.asp is as follows:
Program code:
<%
Dim a(10,10)
a(0,1) = "0x3c" 'Number 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" 'Number 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" 'Number 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" 'Number 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" 'Number 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" 'Number 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" 'Number 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" 'Number 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" 'Number 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" 'Number 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"
%>