On the net, most modern screen readers sit on top of standard Web browsers. You usually control a screen reader by keyboard, not mouse. Braille displays can produce a single line of Braille or many lines. The two fundamental principles in online accessibility are serving everyone and providing alternatives . An accessible Web site functions for any visitor regardless of characteristics they cannot change.
Accessibility revolves around words.
To be accessible, a picture requires words, if not a thousand of them. The words might be written or spoken. When creating soundless Flash animations, in virtually all cases the correct accessibility technique is description. Text or speech. It is, however, difficult to acquire the skill of encapsulating a visual image in words.