You can’t read any webstandard oriented site, without reading something about accessibility. But what makes a site accessible? Here are a few guidelines to follow:
- Provide a text-alternative for all non-text items, like images, forms, objects, … This can most of the time be done with a
alt=""or atitle=""depending on the tag. If more than a few words are required, you can uselongdesc=""for images. - Don’t use colors to make something clear and keep a good contract between your colors. If you ask for a user to click the green link, this will make not much sense to a visually impared visitor (blind, colorblind, …). Use color only for your layout, not for your content.
- Use correct markup. This means if you have a paragraph, use
<p>if you have a title, use a header<h*>(replace the * with a number from 1 to 9, depending on the importance of the header). Don’t use tags like<font>or<strike>. They don’t describe what the text means, but how it should look. Use CSS for this. - Set the document’s language. It a program tries to read a Dutch page in English, the listener will probably not understand what’s on the page. Therefore set your language, use
lang=""in your HTML andxml:lang=""in your XML and XHTML pages. You can define these attributes in most elements. Do so for your<html>and every tag that is in a different language than your main page. Also if you have abbreviations like HTML or CSS, provide the full text also, the first time the abbreviation or acronym occurs. Use the<abbr>and<acronym>tags for it. - Ensure that tables have enough and the correct markup. This means using
<td>for data cells and<th>for header cells. You can also use thesummary=""attribute for the<table>tag. And tags like<thead>,<tbody>and<tfoot>to group your table header, body and footer respectively. To group columns, use<col>and<colgroup>. - If you use new technology on your page, make sure there is also a version available without this technology.
- Make sure the navigation you use is not only accessible or a mouse. Events like
onmouseclick();is therefore not a good option. Also provide accesskey to your most important links using theaccesskey=""attribute. - The text in a hyperlink (text in the
<a>container) should be meaningfull. Use text like: “next chapter” or “download program x” and not “here”. - Use a tableless layout. Tables should only be used to show tablular data, like a list of members or results,…
- Provide labels for your forms. Use the
<label for="">tag, where for refers to the name of the form-element it relates to. Also make sure that the order of your formfields is logical, so that you can use the tab key to navigate. Thetabindex=""attribute can help you with that. - Using W3C compliant code, will help making your page accessible more easy.
If your pages have all of these points covered, your site will mostlikely be accessible.
If you want to check this, try surfing to your site using Opera and disabling color, author stylesheets and images. If you page is still readable, it is accessible.
Maybe a final note. Your listing in search engines will also benifit from making your site accessible.