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An SSI (Server Side Include) allows the webmaster to
include content that is reused on many pages by updating
the content one time. It's also a way to have dynamic
content on your pages within updating the HTML code
or using FTP.
The webmaster is the primary user of the SSI.
SSI (Server Side Include) is a directive that is placed
within HTML pages, and evaluated on the server as the
server sends the page to the browser. It allows you,
the Webmaster, to add dynamically generated content
to an existing HTML page, without having to serve the
entire page via a CGI program, or other dynamic technology.
What's that you say? As a Webmaster,
you can divide your page into parts. For example, these
might be: header, navigation bar, content well, text
insert, site footer, and copyright footer. The parts
that you want to appear on several pages on your site, like the header, navigation
bar, and footers can be stored separately as text files
and imported dynamically into all the pages where they
are used. As you update the content well (that piece
which changes frequently) or any other piece, the browser
assembles the parts dynamically, and the page is displayed
to the site visitor as if the page had been created
as a single unit. In fact, when you look at the source
code from the browser window, it's a seamless unit.
The "magic wand" that "glues" the pieces together
is an SSI.
The advantage of using a server side include in a page
is that the browser builds the page using the latest
version of the included file and dynamically updates
all the pages using that block the next time the pages
are refreshed or loaded by the browser. Thus, blocks
of code that are reused in many pages only have to be
updated once. SSI use can work like frames, without
the disadvantages of using a framed site.
The example in Appendix
A (311K
PDF) uses several
server side includes to assemble designated blocks of
code that might be used repeatedly throughout a related
set of web pages. Using SSI's is a good way to place
headings, navigation elements, News
Box Publisher, Tool
Central NewsPublisher or Calendar
Box Publisher content, as well as local and
site-wide footers in a web page. The text SSI (server
side include) used in this example is processed on the
fly by the server as the page is rendered by the browser
for the site visitor.
Note:
MCPS servers DO NOT support
SSI execs that execute a
program on the server because
they pose a high security
risk to our servers.
The format of the server side include of text is one
line of code:
#include file="filename.txt"
or
#include virtual="/directory/filename.txt"
If the browser can't process this
kind of statement (If browser is too old, pre-Netscape
4.0 or IE 5), it will skip the command and try to display
the include statement as text on the page. To avoid
this situation, we place the command inside of HTML
comment tags thus:
<!-- #include file="filename.txt"
-->
That's it. One line of code tells
the browser "go get this file and insert it here."
It can't be that easy, can it? Well, there are a couple
of other little things you need to do once for each
page. You must use the file extension .shtm or .shtml
instead of .htm and .html. This is simply a naming convention
that says "This html file includes Server commands -
please parse it before delivering to the browser site"
(hence the "s"). That way parsing can be skipped for
all "plain" .html [or .htm] files. Shtml is the default
extension for a page with server-side includes.
The last thing you need to do is keep your friends who
used to view your page at the .htm or .html URL address.
When using the SSI, you're actually changing your home
page name from index.html to index.shtm. If you delete
the old index.html and put up index.shtm, your new page
is the default. It displays in the browser when your
directory is opened and everybody's happy. Few will
even notice that the page name has changed.
But, if a visitor has bookmarked
or linked to the page named index.html, and they use
their bookmark or link to return to your page, it won't
be there anymore. The site visitor will see 404 —
Page not found. What can you do so you don't lose this
site visitor? You can make a redirect page to send those
seeking the old index.html and forward them to your
new page now named index.shtm. An example of this code
is included in How to Make
and Use a Redirect. It's good practice to put up
a redirect to replace the old index.html to avoid frustrating
your site visitors.
The pieces are made in the same way you make your pages.
The pieces, though, only include their part of the page.
You don't need any <html>, <head> or <body>
tags as you need for a complete page. You can preview
your "piece" in your HTML editor the same way you'd
preview an .html page. To make the piece into an includable
file, save it as a text file. Give it an identifiable
name with the suffix of .txt ( i.e. footer.txt) and
save it in your school/office root directory. You'll
need one text file for each include command in your
web page.
Easy as pie... That's the essentials
of using SSI.
To learn more about server side includes see the following
sites.
For questions on using SSI's, contact the Web Services
Team at webmaster@mcpsmd.org
or post questions to the Webmasters Conference on Outloook..
For additional information on
how to implement SSI tags, view Appendix
A in our SSI help document (311K PDF).
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