How to...Web accessibility
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.
Your website must be able to function with all different browsing technologies
This is the first and perhaps 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:
- Handheld device - Very small screen with limited support for JavaScript and large images
- Screen reader - Page content read aloud in the order it appears in the HTML document
- Screen magnifier - As few as three to four words may be able to appear on the screen at any one time
- WebTV - 560px in width with horizontal scrolling not available
- Lynx browser - Text-only browser with no support for tables, CSS, images, JavaScript, Flash or audio and video content
- 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 providing written transcripts
You must also be careful how your pages look when support for CSS and/or tables has been removed. A good way to test for all this is to download the Lynx browser and see if you can successfully access every part of your website.
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! Site visitor may look through your site, decides they like what they see and try to sign up to your newsletter. ...But the form's inaccessible so they click away and you lose a potential customer. Many 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
Prompt text is the text that appears next to each form item, for example, name', email', comments'.
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 19 . 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 browsing through headings and/or links. Make sure 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 . There's more to separating structure and presentation than just laying your web pages out with CSS. You can, and should, avoid using presentational elements as they may cause your website to become inaccessible to certain users. The W3C has provided an HTML element list that tells you which elements are structural and which are presentational .
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 visually impaired users directly to the page content (so they don't have to listen to the navigation options on every page).
