These Web site visitors may experience blindness, low vision, color deficiencies, and so on. The visual disabled rely on sound, touch, and sometimes limited visual input. Screen reader software sends document or page text to speech synthesizers or dynamic braille displays. Screen readers make it easier to navigate documents that are highly structured. Use markup to structure the documents rather than relying on visual cues alone to communicate structure.
Style sheets allow Web site visitors to override author-specified styles.
Users with low vision need large fonts and can configure their browsers. To accommodate these Web site visitors, provide textual equivalents for non-textual information, including images, video clips and sounds. By providing textual equivalents, you go a long way towards making your pages accessible to most of the disabled. This doesn't mean providing separate text-only pages, which can result in having to make and update text only versions of every single page on the site. Instead, it's a good idea to build alternatives directly into the main pages.