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Educational Technologies Center for Life Sciences

Supplement: Naming, Organizing and Installing your HTML Files

Macintosh and Windows users must be aware that not all systems are quite as liberal in terms of the file names they find acceptable. To be safe, observe the following rules in naming files:

  1. Do not have spaces or odd characters in your file names.
  2. Keep filenames short and in lower case. This will make it easier to write references to them correctly.
  3. Each your files should have the appropriate file extension
File type Extensions

.html, .htm

In the early days, web servers were UNIX machines that could handle a four digit extension. Later, when PC or Windows web servers appeared, they had problems handling four digits and so the three digit extension was allowed. Nowdays it no longer matters which one you use.

Microsoft Office Documents

.ppt, .doc, .xls

You can put Powerpoint, Word and Excel documents up on the web for download, though the users must have the corresponding Office applications on their computers in order to be able to read it. It's a handy way of distributing documents, as it involves no special coding or other treatment. BUT you must add the appropriate extension in order for the user's browser to know how to handle it the file.

Note: This is for the standard Office document, not one converted with Microsoft's "Save as Web Page" option, which I don't recommend you use - ever.

Common Gateway Interface


One of the more common ways of creating "dynamic" content - in other words - content that changes without having to rewrite the page. CGI scripts reside on the server in a subdirectory called cgi-bin. They are invoked by special tags you insert in your document. The script can be written in PERL or other language, and may be made available to you for inserting counters, guestbooks, forms, etc. Most of us use scripts already written, though you can write them yourself if you know a scripting language and are allowed access to the cgi-bin folder on your web server.

Server side includes

shtml, shtm

With "server side includes" or SSI, the document contains special tags that indicate the server should insert another file in place of the tag before it sends the final document to the client. This is a common method of inserting a header with the current date or footer containing the date last modified, for example. SSI tags are less complex than the code required for a CGI script, and you insert them directly into your html file yourself. SSI commands will depend on what software your web server is running.



If a text file is given the .txt extension, the browser will display it as text only and will not take action on any embedded HTML tags. Tags will be displayed as text.

Active Server Pages


The page contains Visual Basic Code that the server executes before it sends the final page. This can include adding information from a database, customizing the page based on the user's ID, run other programs, etc. This Microsoft technology allows a great deal of flexibility, but is best left in the hands of the specialist.



The page is composed of a script written in PERL, a scripting language, and like ASP, the page is composed prior to being transmitted.

Graphics Interchange Format


GIF files are graphics files.

Joint Photographer Experts Group

.jpeg, jpg

JPEG files are graphics files

A special name:

To web servers, the names index.html (or index.htm) or default.html (or default.htm) have a special meaning. This is the page that will be loaded when the URL that the user sends specifies a directory, rather than an actual file name. This allows the URL to be shorter, for example:

http://www.life.uiuc.edu/>edtech/html/ will load the default page for this tutorial - which is called default.html - but the file need not be specified in the URL.

Organizing your files:

Have all of the files for a particular project within one folder, and make all links between your files relative to that folder. Images can be placed in a subfolder within the main folder. This makes the transmittal of files go more smoothly and more likely to occur without "broken links".

Installing your files on the Web Server:

After you create your pages you'll need two things:

    1. Space on the web server, which must be set up for you by the administrator.

    2. An "ftp" program to send your files to the web server. FTP stands for "file transfer protocol". HTML files are transmitted as text files; graphics are transmitted as "raw data"

© 2004 - E. Barbara Meyer - EdTech Center - Life Sciences - University of Illinois - Urbana, IL USA