Betsie Technical Outline

What Betsie does

What Betsie does is to rearrange the content on the page in such a way as to make it more legible for people using text to speech converters or screen readers. While some screen readers have a decolumniser built in, Betsie includes BBC specific code to deal with the problem of the left hand navigation bar, which most decolumnisers would place at the top of the page. Betsie knows about the BBC navigation bar and places it at the bottom instead, allowing the user to get straight to the actual content of the actual page.

Betsie has a safe list of URLs that it is allowed to point at. These include anything on *.bbc.co.uk, *.beeb.com and *.bbcworldwide. On a Betsie-enhanced page, any link to a page outside the safe list is flagged with '(External)', so the user knows that following that link may not necessarily lead to an accessible page.

Betsie currently works for almost all World Service, News, Education and Online sites, and for some other BBC sites as well.

A complete summary of Betsie's current functionality is as follows:

• now has a built in 'change settings' page, so the user can specify the font, font size and colour settings of their choice without going via the browser.
• now has support for image maps and stylesheets, which was missing in earlier versions;
• renders as much text as it can in a large, clear font, in yellow text on a black background, so screen readers can easily read it;
• starts sending you the page as soon as it can;
• follows browser redirects, both http and meta tag flavours;
• makes all frames horizontal and does its best to make the result useful.
• automatically removes all table related tags, replacing <TD>s with <BR>s to avoid running cell contents together;
• replaces all IMG tags with their ALT contents (or just deleting them if there is no ALT tag or if ALT="" has been used);
• includes hacks to put the standard nav bar, the news nav bar or the world service nav bar (if present) at the end of the page rather than the beginning;
• with the exceptions below, replaces all links to files on the safe list with links to the relevant parsed version, prefacing all other links with '(external)' so the user knows they won't get a parsed page there;
• removes all Javascript, since there is so much Javascript around that assumes the existence of images and then breaks in Betsie.
• now works with almost all CGI based forms, including search forms, quizzes and dropdown navigational forms.
• includes a link to the unparsed version of the current page (at the bottom);
• deletes any Java and leaves a warning that it has done so (Java cannot be run through a gateway script since Java security would be violated);
• keeps anything embedded with SRC='flashything' such as Shockwave etc intact;
• keeps any Real Audio links intact.

A summary of outstanding issues with Betsie follows:

• Betsie does not work with forms which assume Javascript to be present.
• Betsie cannot eliminate problems with pages that contain syntactically incorrect Javascript;
• does fail on a rough 5% of pages, for various reasons, mainly to do with non-standard implementations of the BBC navbar, or poorly written Javascript.

Download Betsie

The source code for Betsie is now available, together with a licence and set of instructions for installation and setup of Betsie. Unless you are something of a technical expert it may not make great deal of sense to you. Full details are available on the download page.

Betsie Site Contents

This page was last updated on 15th December, 1999.

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