Assistive Technologies

Assistive technologies provide a variety of different ways to help people gain access to the internet.

It is vital for web designers to be aware and understand how these technologies work. People view web pages in many different ways so understanding these methods is key to making your website accessible.

There are three main assistive technologies used :

Speech and braille output

A screen reader and refreshable braille display is one software package that works to output aurally what is seen on a screen.

A screen reader will read HTML code on a page from top to bottom and left to right reading the content, structural coding and textual values of some attributes. For example if a piece of text is coded using header tags (H1 etc) the reader will identify this as a heading. Alt text used for images, page titles, summaries, lists etc can all be identified by the reader to provide the structural image of the page.

Clearly labelled links are crucial as they are not read in context. A link that says "read more" will be read by the reader as "Link, read more", this does not tell the user which page they are linking to.

Good use of headings, alt text and links are key to effective navigation.

Screen Magnification

Screen magnification magnifies the screen. The greater the degree of magnification results in less information displayed on the screen. In extreme situations only two or three words are displayed on the screen at one time.

Images become blurred and pixelated when magnified so text images become illegible. This would make navigation vurtually unusable if images of text are used as links.

Large areas of blank space between text and elements can be a problem too. In magnification it will be necessary for the user to scroll through an even larger area of space and may miss valuable information.

For magnification users consistency is key to layout and navigation.

Text-base browsers

Lynx is a frequently used text-base browser that cannot be used with a mouse. The content of a web page is displayed as text and will not support images.