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We are trying this tutorial to be simple, so in this page we will request
imagenes from a ".asp" page, but the imagen will not be newly generated.
The images will be already saved in our server .
First, letīs check this two pages:
| showpicture.html |
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<html>
<title>My picture</title>
<body>
<img src=mypicture.asp>
</body>
</html> |
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| mypicture.asp |
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<% response.ContentType ="image/GIF" %>
<!--#include virtual="mypicture.gif" --> |
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- In the first file (showpicture.html) we have include in the html code the
source for our picture ("mypicture.asp", instead of "mypicture.gif").
- In the response page, first we have indicated whith kind of ContentType we
are sending to the client (this time "image/GIF", and then by using
"include/virtual" the file is send (in this case all files are in the same
directory)
Letīs try an examples:
A rudimentary banner rotator
system
Our page is "mypage.html" and we are requesting a picture to a file named
"mypicture.asp". This file will send to the client one of the pictures available
(in this case up to 5), and two variables will be set up:
- session ("ad"): will be used to save a number, which is needed to
determinate which ad to show each time
- session ("linkto"): will be used to save the link corresponding to the ad
shown.
| mypage.html |
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<html>
<title>My page</title>
<body>
<a href=adrotatorlink.asp><img src=mypicture.asp NOSAVE></a>
</body>
</html> |
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| mypicture.asp |
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<%
if session("ad")="" then
session("ad")=0
end if
if session("ad")=5 then
session("ad")=1
else
session("ad")=session("ad")+1
end if
response.ContentType ="image/GIF"
%>
<% Select Case session("ad") %>
<% case 1
session("linkto")="http://linkto1.com" %>
<!--#include virtual="picture1.gif" -->
<% case 2
session("linkto")="http://linkto2.com" %>
<!--#include
virtual="picture2.gif" -->
<% case 3
session("linkto")="http://linkto3.com" %>
<!--#include
virtual="picture3.gif" -->
<% case 4
session("linkto")="http://linkto4.com" %>
<!--#include
virtual="picture4.gif" -->
<% case 5
session("linkto")="http://linkto5.com" %>
<!--#include
virtual="picture5.gif" -->
<% End select %> |
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| adrotatorlink.asp |
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| response.redirect(session("linkto")) |
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"mypage.html"
At "mypage.html" we have include the regular HTML code to
show a picture. We have used within the code the instruction "NOSAVE", so the
picture will not be saved in the clients cache.
"mypicture.asp"
- Lines 2-3. Each time a new visitor gets to
"http://www.mysite.com/adrotator.asp" a new session will be open, and by
using the session
method, we will define session("ad") value to 0. In case the visitor is not
new, the value for session("ad") will exits, and that value will be keep.
- Lines 6-10. The value for Session("ad") is increased by one
unless that value is 5 (which is the maximum value allowed in this script)
- Line 12. The ContentType is defined
- Lines 15-31. By using Select_case
and depending on the value saved in the instruction session("ad"), we will
define session("linkto"), which will be the url to which we will redirect our
visitor in case the picture send to the browser is clicked.
"adrotatorlink.asp"
After clicking the corresponding picture, and as we have already
save the corresponding URL at session('linkto"), we will redirect the visitor
to the correct URL. NOTE: By using "NOSAVE" code in our
page, the client will no save the picture in the cache of the computer. It may
be a problem for us: letīs suppose we have include this the same code in several
pages within our site. Each time we visit a new page, session ("linkto") will be
defined again, but in case the visitor clicks the back bottom of the browser and
the picture show is the same one it was shown in our previous visit, when
clicking the visitor will be redirect to a non-correct URL.
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