Crawford Design

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User Control

Avoid Flickering Elements on the Screen

Web pages should not contain elements that flash more than three times in any one second period. Avoid blinking banners, Flash animations etc. that could cause someone to have a seizure.

Auto-redirect

Provide the ability to stop auto-redirect and do not use markup to redirect pages automatically. The server should be configured to perform redirects instead.

Auto Refreshes

Do not set a page to auto refresh after a certain period of time. Persons with disabilities may take longer to read a page or fill out a form. Refreshing pages and changing content or clearing a form by refreshing could cause great frustration to a person with disabilities.

Auto-updating

For any auto-updating information that (1) starts automatically and (2) is presented in parallel with other content, there should be a mechanism for the user to pause, stop, or hide it or to control the frequency of the update unless the auto-updating is part of an activity where it is essential. For example, rotating Flash content should have a pause button to allow a user more time to read the content.

Timing

Ensure that users have enough time to complete a task. Avoid putting time constraints on an activity like completing a LearningLink module. If time constraints are required for an activity allow users to pause the activity, turn the time restraint off, or give a user the option to lengthen the time limit.

Popups and Browser Window Control

Do not cause spawned popup windows to appear and do not change the current window without informing the user.

Audio Control

If any audio on a web page plays automatically for more than 3 seconds, either a mechanism should be available to pause or stop the audio, or a mechanism should be available to control audio volume independently from the overall system volume level.

Text Resizing

There should be the capability to resize text, without assistive technology, up to 200% without loss of content or functionality. Most modern browsers offer the ability to magnify the screen beyond 200%. Creating custom text resizing functionality for Web sites may not be necessary when legacy browsers (IE 6) are no longer used.

Keyboard Accessible

Allow users to use the tab key and up, down, left and right arrow keys to navigate through a Web site or application. Avoid creating keyboard navigation for HTML Web sites by using the accesskey attribute because it is not supported uniformly across browsers. User agents such as JAWS or IBM Home Page Reader use keyboard navigation.

Keyboard navigation may not work for Flash.

References