3.4 DATA FORMATS

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The format of the data is important so that other programs may interpret it correctly.

3.4.1 HTML - Hyper Text Markup Language

This is a format that is invisible to the user on the web. It allows documents to be formatted to fit the local screen.

Editors are available that allow users to update HTML documents the same way they use word processors.

3.4.1.1 - Publishing Web Pages

Once a web page has been modified it is necessary to put it back on the web server.

When publishing a page with a browser `FTP' will be used.

The web page called `index.html' is the first one to be returned. If you are publishing a main page your main page should be called `index.html'.

Keep in mind that the website is just another computer. You have directories and files there too. To create a web site that has multiple files we need to create other files or directory names.

Note that some web servers do not observe upper/lower case and cut the `html' extension to `htm'. Microsoft based computers are notorious for this, and this will be the most common source of trouble.

3.4.2 URLs

In HTML documents we need to refer to resources. To do this we use a label to identify the type of resource, followed by a location.

Universal Resource Locators (URLs)

- http:WEB_SITE_NAME

- ftp:FTP_SITE_NAME

- mailto:USER@MAIL_SERVER

- news:NEWSGROUP_NAME

3.4.3 Hints

Below is a list of hints for publishing web pages

- Windows will not allow multiple applications to open the same file at the same time. If you seem to be having trouble opening a file, make sure it is not open in another application.

- As you add other files to your homepage, put them in the `temp' directory. This will make all of the procedures simpler.

- Try to make your web pages small, and link them together. This will decrease download time and make browsers happier.

- Avoid using excessive images. Anything over 10K will make it very slow downloading over modem. Anything over 100K makes modem downloading painfully slow.

- When putting images on the web page use `jpg' for photographic images, and `gif' for line images. `jpg' images can be compressed more than `gif', but lines will become blurred.

- To link to other files or web pages there will be a `link' command. If you want to add a file that is in your `temp' directory, just put the name of the file in the `URL' field.

- Watch upper/lower case. This is a major cause of web page problems.

3.4.4 Specialized Editors

There are a variety of editors that will allow us to edit single web pages or entire sites.

These programs include,

- Microsoft Word

- Powerpoint

- WebCT

- Frontpage

3.4.5 PDF

A format proposed by Adobe. This is not a `standard', but is very widely accepted.

When documents are presented in pdf format their original layout is preserved (HTML will actually change the look/layout of a document), but the files become hard/impossible to work with.

A special plug-in is required to view these files.

3.4.6 Encryption

Allows some degree of privacy, but this is not guaranteed.

Basically, if you have something you don't want seen, don't do it on the computer.

3.4.7 Compression

We can make a file smaller by compressing it (unless it is already compressed, then it gets larger)

File compression can make files harder to use in Web documents, but the smaller size makes them faster to download. A good rule of thumb is that when the file is MB is size, compression will have a large impact.

Many file formats have compression built in, including,

images - JPG, GIF

video - MPEG, AVI

programs - installation programs are normally compressed

Typical compression formats include,

zip - zip, medium range compression

gz - g-zip - good compression

Z - unix compression

Stuffit - A Mac compression format

Some files, such as text, will become 1/10 of their original size.