Skip Quick Links

Standards-based markup is the foundation of web accessibility. Web pages that adhere to markup standards like XHTML and CSS (Cascading Style Sheets) are accessible to existing assistive technologies, and will continue to be accessible to future browsers and technologies. Standards-based markup is a way of "future-proofing" web content.

Importance of Standards-Based Markup

Standards-based markup separates content, structure, and display. This is important because content (the information on a page) must be available to different accessibility technologies, as well as displayed differently for people with different disabilities. For example, visual content must also be presented non-visually for the blind. Similarly, structure must be separate from presentation, and clearly indicated as structure, to make it available for interpretation by accessibility technologies.

Early versions of HTML (HyperText Markup Language) did not do a good job of separating content, structure, and display. Later versions – and the browser manufacturers themselves – introduced display markup like the now-deprecated <font> tag. HTML 4.01, along with CSS, was issued to again separate display from structure and improve accessibility.

This section provides an overview of the two primary standard markup languages: XHTML (the latest incarnation of HTML 4.01) and CSS. These two technologies allow the developer to separate content from presentation.