If you think you have something to add to this list, drop us a line at email@example.com and we will see about adding it to this site for the benefit of all. However, it is not my intention to duplicate any of the very useful general HTML Style Guides that can be found on the Web. (There used to be a few, but now there are hundreds -- use a Web search engine to look for "HTML style guide" and you will surely find some useful information.)
Once you design an effective page, use it as a template for all other pages. This will make your site easier for all users to navigate. Knowing how important information is laid out and where to find buttons and menus will make your site a very friendly one. Remember, in most cases your page is not for your personal enjoyment, but for the use and benefit of others who are visiting.
The easiest way to ensure a minimum level of accessibility is to write HTML that conforms to the HTML version 2.0 standard.
You might be surprised to see how the wonderful, complex page you designed for one browser looks with a different browser. Netscape Navigator may be the most popular web browser, but there are a huge number of people who use other, less well-known systems.
I am guilty of this sin: I design my graphics or capture photographs at the highest useable resolution and colour-depth that my PC supports -- and why not? I paid for a 64-bit graphics adapter and a good quality monitor. Well, I forgot how astoundingly bad a 24-bit per pixel (true-colour) image can look when you view it with a 256 colour (super-VGA) or 16-colour (VGA) adapter. The wonderfully harmonious colours I chose or scanned are probably all gone, and what is left may be a dithered mess. Text that is incorporated in a graphic image or appear against a BACKGROUND file may be almost entirely unreadable if the colours change or appear badly dithered. This is true of some of the graphics that appear on this site... I will be reviewing and revising them shortly.
Be clear when using date formats.
Imagine this situation just eight years from now, in the year 2004:
This page was last updated 01/02/03
Depending on the country you live in, or the standard you are familiar with, that date could mean February 1, 2003 or January 2, 2003 or February 3, 2001 or even March 2, 2001.
In other words, this date format is practically useless. Even today, when the year field is unambiguous, the day and month fields change position depending on country or personal preference.
Vertical lists of links are more accessible to people using screen readers with graphical browsers than are multiple links on one line or in one sentence.
Avoid multiple links on the same line. Users with screen readers will often read the "current line" to determine the context of the cursor or highlighted word. Thus, if there are three links on the same line, each will produce the same result with a current-line-read.
Apparently, some screen-readers lock-up when they encounter blinking text.
I admit this is hearsay. If anyone can verify this I would appreciate hearing from you. However, beyond any concerns of accessibility, almost every HTML style guide I have seen warns designers against using the <blink> tag. The consensus is that it is more annoying than eye-catching.
Screen-readers interpret punctuation for the listener. Lists, headings or titles without punctuation may be run together by a screen-reader, making it difficult for the listener to understand. To a sighted user, headers are separated and emphasized to stand out. List items are separated by bullets or numbers: the beginning and end of an item are easily determined visually, but such lists may be confusing to a visually impaired user.
I missed this one! It was pointed out to me by Michael Paciello of Digital Equipment Corporation that graphical aids are useful for some persons with learning or intellectual disabilities. The button bar can be individual .GIF files or an IMAGEMAP. Just remember to keep the same buttons and the same location on every page. Also, don't forget to give a text-only alterative for users who cannot view graphics.