When creating accessible websites, most web developers and web managers tend to follow the W3C accessibility guidelines. And rightly so - they are the most comprehensive accessibility resource on the Internet after all.
The W3C accessibility guidelines, or Web Content Accessibility Guidelines as they're officially known, could go slightly further however. Fulfilling the guidelines will give you a very accessible website (remember though, they are just guidelines so shouldn't always be taken literally). For ultimate accessibility though, try implementing some of these techniques too:
Hidden text can be very useful for screen reader users. If there isn't sufficient text for these users to gain an understanding of a particular section, then you can simply create this extra information and hide it from sighted users.
The most common and useful page items to insert invisible text for screen reader users include:
As a method of browsing through a page, screen reader users can call up a list of links on a page and jump to the link in which they're most interested. It's common knowledge that link text should make sense out of context, and this is indeed a W3C guideline. Link text such as 'Click here' would obviously make no sense in a list like this. It's also crucial that link text is:
Link text is additionally important for users that finds it difficult to read online, such as screen magnifier users and those with learning difficulties and dyslexia. For these users when they scan through web pages, they'll often be unable to make out specific words - instead, they'll see shapes and colours. Anything that's in a high contrast colour is obviously a link, so they can stop and read it.
By making link text succinct and front-loaded, and using conventional link text, it's far easier for users that finds it difficult to read online to immediately comprehend links and what their destination is.
It's crucial that text is resizable for web users with poor or limited vision - or so the theory goes. In actual fact, user testing has shown time and time again that few web users actually know how to resize text, or that this functionality even exists.
By providing a visible font resizer all users are of course made aware that they can resize the text should they need to. To find out how to put a font resizer on to your website, read this article about stylesheet switching.
(Incidentally, if you don't know how to resize text simply select 'View > Text size' in either Internet Explorer or Firefox; alternatively, scroll with the wheel of your mouse whilst holding down the control key.)
If you provide instructions for any kind of functionality on your site, make sure that the instructions are placed before the functionality. This of course sounds obvious, but it's amazing how many times this rule isn't adhered to.
Screen reader users listen to pages in the order that they're written in, so if any instructions come after what they're relating to then that's obviously going to be too late.
Placing instructions first is also crucial for screen magnifier users. Screen magnifier users can only see a small section of the screen at any one time, so if instructions are placed in an out-of-the-way place they'll likely be overlooked.
Web forms are perhaps the most common type of functionality to contain instructions. Do be sure that any instructions are placed above the form and not below it. Mis-placed instructions usually include explaining which fields are required and error messages.
Headings are crucial for all users to find what they're looking for quickly and efficiently. They are however particularly useful for any user that finds it difficult to read online, such as screen magnifier users and those with learning difficulties and dyslexia.
When these users scan through web pages, they'll often be unable to pick up words and instead will see shapes and colours. By using a large font size for headings, these users will easily be able to spot these important headings.
Keyboard-only web users can navigate through web pages by tabbing from link to link (and form item to form item). It can however sometimes be difficult to know exactly where you are on the page when relying on the tabbing method. By assigning a background colour to the focus state of each link, it becomes much easier for these users to orientate themselves on the page.
Many web users with dexterity problems will use only the keyboard to browse through a website. Some will still continue to use a mouse but with rather limited control, so wherever possible do try increase the area of the link target. This is of course not possible for regular links, but for vertical based navigation lists it's easy to extend the clickable area to the full width of the column by assigning the style,
display: block to each link.
The W3C accessibility guidelines are of course important, but if you want your website to be truly accessible then there's more that you can do. Following the advice in this article is of course a great start!
This article was written by Trenton Moss. He's crazy crazy about web usability and accessibility - so crazy that he went and started his own usability and accessibility consultancy (Webcredible) to help make the Internet a better place for everyone. He's extremely good at running focus groups and likes to conduct a website evaluation as often as he can.09 dec 2003 - 2807