Over the last few years, more and more basic services have been moving to the Web (banking, paying bills, canceling utilities, etc.) Whether the move is initiated as a cost-saving device or as a way to make the services more readily available, the fact is that moving every day "life administration" online means accessibility gains in importance.
Web accessibility is a broad topic but in essence it means your pages are accessible by people using a wide range of user-agent software and devices, in addition to the standard web browsers. The foundation for achieving accessibility is separating out the content and structure from the presentation and behavior of a page.
Use semantic markup to structure the document.
Semantic markup provides a framework for explicitly describing things. It is descriptive enough to allow machines to recognize it and make decisions about navigating a page. For example, the use of header tags <h1> allows users of screen readers to scan the headers on a page. Or a <strong> tag allows an oral user agent to apply a different voice for emphasis. An added benefit is that semantic markup still gives the content visual hierarchy even if the external style sheet fails to load.
Use CSS instead of presentational markup.
Style sheets define presentational characteristics. Presentational markup (e.g., <font>) does that as well, but it does not allow a user to adjust the presentation to suit their needs. When presentation is defined in a style sheet, it allows different users to override the author’s styles with their own. This way, a visually impaired user can display a large text alternative by defining his or her own user style.
Ideally you want to use external style sheets so the presentation information for the site is held in one place and can be updated quickly. In addition, external style sheets enable you to have consistency across pages and implement global changes in just one file.
The Web Accessibility Initiative of the W3C, of course, has extensive guidelines and details on how to achieve web content accessibility. It’s worth reviewing and implementing because after all, you want your site to reach the largest possible audience. Web accessibility increases the odds of doing just that
