Many sites are technically accessible, but score low on usability for keyboard and screen reader users. Though the usability of frames for keyboard or screen reader users (or any other users) may still be debated, we chose them for the layout of the Math Description Engine website believing it would give all users a clear view of the site layout and the logical reading flow. NASA websites have standard header and footer sections and the frame layout enables quick keyboard navigation past them. It also should allow easy navigation between the two most used areas: the navigation menu frame and the main content frame.
If you have problems or comments regarding the use of frames or any suggestions regarding site accessibility and usability, please let us know. The site has been tested in multiple browsers, including Lynx. The frames version works with Lynx. There is also a no-frames option. More information on the site layout and other usability information follows:
The tab order among frames is: 1. top, 2. middle, 3. middle-left, 4. middle-right, and 5. bottom. The top frame contains the NASA header and MDE product banner. The bottom frame contains the NASA footer.
The middle frame contains the navigation frame and the main content frame. Selecting a menu item in the navigation frame will display the selected page in the main content frame.
Use your screen reader's frame navigation keys to move quickly between the navigation and main content frames. In Jaws, for example, M and Shift+M move to the next frame and previous frame respectively. The tab order of the page with or without a screenreader follows the same top, middle-left, middle-right, bottom flow.
There is one navigation menu for the site's main content. it does not grow, shrink, nor cause submenus to be displayed. As the site content grows, if different menu displays are appropriate, this description will be updated to describe them.
Headers, lists and other structural elements are used to convey page structure. You may find it convenient to navigate between the Navigation and Main Content Frames by using your screen reader's jump-to-heading shortcuts.
Where appropriate to display a page outside the frame structure (as with this page, for example) the page will be displayed in its own window. Depending on the context, this may be a new window. Links to non-MDE content will open in a new browser window, for example. The MDE API Javadoc, and non-html files also display in their own windows. Link titles are used to alert the keyboard user to new window links.