This is a WebCom FAQ. It provides information on common errors made when creating links to other files.

• Incorrect URL syntax
• Filename case sensitivity under Unix ("bob.gif" and "BOB.GIF" are not the same file)
• Relative links stop working after form is submitted
• More information

The most common error when creating hotlinks to another file is:

Including "www" in the URL:

• Proper syntax: /guest/welcome.html
• Improper syntax: /guest/www/welcome.html

All links to pages and files accessible through the Web must be located within the "www" directory located in your home directory. To prevent people from having access to non-public files, the WWW Server looks underneath this directory for any files referenced in a URL.

This also means that any files referenced in your Web page must be located under the "www" directory. I.e. files must be placed in "/pub/youruserid/www/graphics" and not "/pub/youruserid/graphics".

Unix, the operating system on which the primary WebCom Servers run, uses a file system which distinguishes between capital and lower case letters when naming files. Under Unix, the filenames "bob.html", "BOB.html" and "BOB.HTML" all refer to different files. This is not true for other operating systems (such as MS-DOS or Windows), which use do not distinguish case in recording a file's name (or more accurately always record a files name in all caps.).

If your link points to "BOB.HTML", and the file is actually stored as "bob.html" on the WebCom Server, you will receive an error message "NOT FOUND" when the link is selected. Some FTP clients will use all capitals for the filenames when they are transferred, others may not.

If a special screen has been designed to appear after a form submission, relative links to pictures and in hyperlink references will suddenly not work. This is because, as you can observe, the address that appears in the URL box of a browser of any form submission confirmation screen is /cgi-bin/form. Thus, relative links would use this as their base.

To overcome this problem, place a <BASE HREF> tag in the HEAD section of the confirmation page, such as:

<BASE HREF="/userid/path/filename.shtml">

Another technique for tracking down errors in your links is by using online HTML validators, which can reveal syntax errors.

For more information on correct hotlink syntax, see Hotlinks to Other Files.