Flash

Flash is a proprietary technology owned by the Adobe company (formerly Macromedia).

Truth

Flash provides interactive animated graphics and sound capability via a browser plug-in, i.e. an accessory to your browser.  Some people do not have this plug-in installed.  Some do not want to install it.

Proper functioning of Flash depends not only on the server that hosts your site, but also on the Macromedia server.

Flash material tends to be much larger (in bytes) than static images. 

Material in a Flash presentation is not indexed by search engines.

Text in a Flash presentation cannot be resized by the user.  Some Flash presentations do provide a Zoom function, which enlarges a portion of the image while clipping the rest of it.

In 2002, Flash added significant accessibility capabilities, including an interface to text-to-speach functions within the user's operating system.  Few web sites take advantage of these capabilities.  Some audio user agents cannot do anything with Flash material.

Consequences

If the user does not have the Flash plug-in installed and declines to install it, they will not see any Flash material.

It may take a long time for a Flash presentation to load.  Users with narrow bandwidth may skip the Flash (if possible) or leave the site prematurely.  (See Bandwidth and page size). 

If the Macromedia site is down or is saturated by global traffic, visitors to your site may wait a lengthy time for the Flash material to download.

If most of your material is inside Flash presentations, there will be little or nothing for search engines to index on your site.

Users with even mild vision impairments may not be able to view Flash material unless you have made the extra effort to make it accessible.  This effort is not trivial.

Recommendations

Design your site making the assumption that Flash is not available.  Implement accessibility.

Tips

  1. Use Flash only to augment your content, not to provide it.
  2. If the Flash material starts automatically, always provide the user with an option to skip it and move on to the actual site content.  This option should remain available until the Flash material has completely loaded.
  3. When Flash material is loading, provide a progress indicator which gives the user some idea as to how much longer the loading will take.  This allows the user to make an informed decision about whether to wait or to skip the Flash presentation.
  4. Use the accessibility features in Flash to provide content for users who are blind or have mobility issues.  See the information on accessibility from Adobe.

Index

Last revised 7 Nov 2009