WebbIE: a Web Browser for Visually Impaired People

Webpages are documents written in Hypertext Mark-up Language (HTML) defined by the international web standards body, the World-Wide-Web Consortium (W3C) HTML . HTML combines text information with meaningful semantic mark-up of the text, for example “This is a header” or “this is a list of information”. An HTML client has responsibility for rendering the content to the user in accordance with the mark-up. For example, text indicated as “header” text in HTML might be rendered in a large, bold font in a visual client, spoken at a louder volume in an audio client or explicitly labelled with “Headline” in a text-only client. Having written a document in HTML, the author can provide formatting information for a particular medium using the related Cascading Style Sheets (CSS). These contain information on how the author wishes the information to be presented that may be used by the client, so a visual Stylesheet might instruct the client to use a particular font or colour combination, and an audio Stylesheet to use a particular voice or volume. This approach separates content (HTML) from presentation (CSS). The the end user should thus be able to view the document as intended by the author (using their CSS) or to access the content in a manner more desirable or practical for the user (using the HTML). In practice, however, the web is primarily a visual medium, and the principle of separating content and presentation has not been honoured. Presentation information has been included in HTML mark-up. This has repercussions for access by users of non-visual clients. For example, HTML tables, designed to contain information best presented in a tabular format (for example, arrays of number), are often used as layout containers to position content on the screen for the visual user. This can break up the normal flow of a document when viewed in a linear manner, as with a screen reader, and frustrate resizing and reformatting of content for the