Tips for accessibility

5. Avoid the use of flickering and blinking contents

Some people, e.g. people with photosensitive epilepsy may have seizures triggered when they encounter fast flickering or blinking objects. Some users, e.g. old people, may not be able to read fast moving information or have difficulties in manipulating fast moving objects.

Some sites use the META parameter for automatic refresh of a certain section of a web page, e.g. an advertisement section of the page, so that users will see a new advertisement at every pre-defined interval. Such feature will distract the user's attention by interrupting the user whenever refresh of the given section occurs. This is due to the fact that some assistive tools respond to changes in the current web page and will switch to read the changed contents as the change occurs. Thus the normal reading sequence of the user is interrupted.

Suggestions

• Avoid the use of flickering and blinking objects / contents especially those moving at a fast rate.
• For moving objects that require manipulations e.g. a rolling / scrolling ICON / banner with hyperlinks, the object could be paused when the user put the mouse over it so that they can click at the embedded hyperlink.
• Avoid the use of automatic refresh.

Example of the use of auto-refresh display