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Posted 14 Jun 2004

Web accessibility: The basics

, 14 Jun 2004
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What is web accessibility & why is it important?


Web accessibility is about making your website accessible to all Internet users (both disabled and non-disabled), regardless of what browsing technology they're using. In addition to complying with the law, an accessible website can reap huge benefits on to your website and your business.

Please read the articles, Benefits of an accessible website - part 1 and Benefits of an accessible website - part 2 for more about the importance of web accessibility.

Your website must be able to function with all different browsing technologies

The first and perhaps the most important rule of web accessibility. Not everyone is using the latest version of Internet Explorer, with all the plug-ins and programs that you may require them to have for your website. Different browsing technologies can include:

  • Lynx browser - Text-only browser with no support for tables, CSS, images, JavaScript, Flash or audio and video content
  • WebTV - 560px in width with horizontal scrolling not available
  • Screen reader - Page content read aloud in the order it appears in the HTML document
  • Handheld device - Very small screen with limited support for JavaScript and large images
  • Screen magnifier - As few as three to four words may be able to appear on the screen at any one time
  • Slow connection (below 56kb) - Users may turn off images to enable a faster download time
  • 1600px screen width - Very wide screen

This basically means that you must provide alternatives to:

  • Images - in the form of ALT text
  • JavaScript - through the <noscript> tag
  • Flash - with HTML equivalents
  • Audio & video - by using written transcripts

You must also be careful how your pages look when support for CSS and/or tables has been removed.

There are two good ways you can test for all this:

Forms need to be accessible to all web users

When a web user fills out a form it's a great thing. People fill out forms to:

  • Buy a product
  • Sign up to a newsletter
  • Ask a question

These are the goals of your website! A site visitor may look through your site, decides he likes what he sees and tries to sign up to your newsletter.

...But the form's inaccessible to him so he clicks away and you lose a potential customer. Most forms on the web are inaccessible. The two main reasons for this are:

  • Prompt text is incorrectly positioned
  • Prompt text is unassigned to form items
<p(prompt />

To find out more please read this article about making your forms accessible.

It should be easy for all users to quickly process the content on your website

We generally don't read web pages. We scan, trying to find what we're looking for as quickly as possible. On a regular monitor, we scroll down the page looking at the items that stand out from the rest of the text: headings, links, bold text and bullet points. Non-keyboard and visually impaired users often scan pages by tabbing between headings or links.

Make sure that you use headings, links, bold text and bullet points and that they contain descriptive text. For example, never use 'click here' for link text.

Structure and presentation should be completely separated

By separating structure and presentation your website will be flexible enough to be ready for the future of the Internet: PDAs, mobile phones, in-car browsers, WebTV and 1600px screens.

The structure of a document is how it is organised, usually with navigational menu items, headings, sub-headings, paragraphs, lists, and links. The presentation of a document is how these words and images are presented to the end user.

The main principle behind this is to use CSS and not tables to lay out your web pages. Check out HTML Dog for some great CSS tips and information.

There's more to separating structure and presentation than just laying your web pages out with CSS. Have a look at this HTML element list that tells you which elements are structural and which are presentational. You can, and should, avoid using presentational elements as they may cause your website to become inaccessible to certain users.

The end user should have control over your web pages

All web users have unique requirements for how they use the Internet, depending on the kind of browser they're using or any kind of handicap or disability they may have. By handing control back to your users they'll be able to use your website in the way that best suits them.

This could mean allowing users to resize text, warning them when links are going to open in a new window, or providing a link at the top of the screen that takes the user directly to the page content.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Trenton Moss
Web Developer
United Kingdom United Kingdom
Trenton Moss is crazy about usability and accessibility - so crazy that he founded Webcredible, an industry leading user experience consultancy, to help make the Internet a better place for everyone. He's very good at information architecture and interaction design.

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