AJAX time machine

Many modern Web pages update parts of their content, and this is often automatic. This allows a 'clean' user-interface and information-rich pages. Keeping up with updates or recovering from mistakes can be a problem, however, as it is often not possible to revert a page to a previous state. This can be particularly problematic for users with poor literacy or cognitive disabilities, the elderly, or for users of assistive technologies. For pages that use these technologies to be truly accessible for all, they must afford users sufficient control over updates, to allow them to read and use the information available before it disappears forever. While applying good practice during page design and implementation can provide this, there are many pages for which information changes too rapidly for the user. We propose to supplement assistive technologies with a Web page 'time machine' that will allow users to review all the states a page has been in, and to step backwards or forwards through these states at their own pace.