Archive for the ‘interactivity’ Category

Graceful Degradation is Important

January 25, 2008

Graceful degradation is the ability to continue working, albeit with reduced functionality, when some expected capability is absent.

Example: Suppose you use JavaScript in your web page to enhance its interactivity. Your web page degrades gracefully if it continues to function even in a browser that has JavaScript turned off.

This is an example of an HTML link that degrades gracefully:

<a href=”http://solarsystem.jpl.nasa.gov/planets/profile.cfm?Object=Mercury” onclick=”…”>Mercury</a>

If JavaScript is turned on in a user’s browser then the onclick=”…” will be executed. If JavaScript is turned off then the browser’s default behavior ensues: the browser fetches the web page identified by the href value, and replaces the current page with it.

Design your web pages, your software, your machines, your whatever to degrade gracefully. Anticipate things that might be absent or turned off and make your system able to still function.