Troubleshooting an HTML Document
 

Module W27c (v. 1.2)
 

How to Troubleshoot - Some Rules to Live By

Summarized from "The Power of the Most Likely", by Bob Colwell (Computer, October 2002, pp.12-14)

  1. Keep notes about what you've tried that didn't work.
  2. Change one thing at a time.
  3. Don't ignore the unexpected - "Unquestioned assumtions are by far the biggest time-waster for system debuggers."
  4. Follow the problem wherever it leads, whether you like it or not.
  5. Simplify complex situations to a series of simple situations.
  6. Debugging demands attention - don't let yourself get distracted.
  7. Bugs usually live in colonies - if you know there's one, look for more.
  8. Test your equipment - is it a browser problem?
  9. Know when to "call in the cavalry" - don't keep going around in circles.
 

Common Problems in HTML
Symptom Possible Cause Possible Fix
You make a change, but it doesn't show in the browser You're looking at one file and fixing another

Check the file's:

  • Extension (htm or html?)
  • Directory location

Change file name as needed
Image doesn't show when browsing on workstation Image file name or location aren't the same as in the image <img...> tag

Check the file's:

  • Extension (jpg or jpeg?)
  • Directory location

Change either file name or location, or image tag.
Image showed on the workstation, but doesn't show when browsing on the server.
  1. Capitalization of the file name is different from capitalization in the image <img...> tag
  1. Check the file's exact name using FTP. Use only lower-case file names to keep things simple. Change either the image tag or the file name to eliminate capitals.
  1. Image file was corrupted while being transferred to the server.
  1. Re-transmit the image file to the server, making sure the FTP program is set to binary mode.
Nested list doesn't indent when it should. Outer list was closed prematurely. Remove </ul> or </ol> when starting the inner (nested) list. The outer list should only be closed after the inner list is complete.
Nested lists don't pop out when they should, resulting in an inverted stairway.
  1. Inner list was not closed when it should have been.
  1. Put </ul> and </ol> tags at the end of each list, where the next item should be out farther.
 
  1. Another list was started when the outer list should have been allowed to resume.
  1. Leave in </ul> and </ol> tags at the end of inner list, but remove the <ul> or <ol> tags for the out list - they will resume on their own.
Absolute link (complete URL) doesn't work. Typo Don't type URLs into HTML code. Instead, navigate a browser to the linked page, click in the Location or Address window, and <Ctrl>C to copy the URL. Paste it into the HTML code.
Relative link (within the same Web site) worked on your computer, but doesn't work on the server. Inconsitent capitalization Make sure links and file names use the same capitalization. Your life will be much simpler if you use only lower-case letters.

 

L. Krieg, Washtenaw Community College