HTML and CSS Reference
Flash is extremely inaccessible. In most cases, a Flash site might as well be a black box to blind users, and it is
often hostile to color-blind, deaf, and motion-impaired users as well. Although accessibility has been improved
somewhat in the latest versions of Flash, most Flash applications are still vastly less accessible than plain old
It's not just handicapped users who have problems with Flash either. Even people with no handicaps do not
have Flash-enabled browsers or browsers with the latest version of Flash installed. The lowest estimates I've
seen are that 1 person out of 20 does not have Flash installed. Based on my experience, I expect that number is
severely biased by self-selection effects and that likely a much higher percentage of users do not have Flash at
all. Regardless of the exact numbers, though, there's no question that Flash is a crippling inconvenience to
Finally, Flash is almost completely inaccessible to Google and other search engines. Even if users can view a
Flash site, if it's all Flash, they'll never find it. My book agent (who's also an author and professor) recently
converted to an all-Flash site. If you search for his name on Google, you'll find his faculty page, his Amazon
page, his Barnes & Noble page, some listings at other bookstores, some eBay listings for his topics, and more
detritus no user would ever wade through. It isn't until the fourth page of Google results, near the bottom, that
his literary agency that shares his name shows up.
There are some things you can't do in plain old HTML. If you really want a bouncing, singing greeting card or
another Tetris knockoff, go ahead and use Flash.
There are even some more serious uses to which Flash can reasonably be put. For example, a Flash animation
can show how to disassemble a complicated piece of equipment or demonstrate the flow of money in an
economy. Done well, such animations will assist sighted users. However, you should also have a complete plain
HTML version of all such content, for both unsighted users and Google.
Flash is sometimes used to attempt to lock in content. Flash content cannot be copied as easily as HTML and
than downloading their own copies of videos. However, there's a world of difference between "cannot be copied
as easily" and "cannot be copied." Numerous tools are available today that enable users to download Flash
videos, decompile Flash files, and extract text, images, and movies from them. Encoding content in Flash
merely impedes legitimate users while not seriously hindering pirates.
Chances are you probably know where the Flash files are on your site. If for some reason you don't, just search
for d27cdb6e-ae6d-11cf-96b8-444553540000 and application/x-shockwave-flash . Unless you're publishing
Flash tutorials, these strings only appear in documents that embed Flash.
Once you've found a Flash file, you'll need to play it to see what it's doing. If it's doing something that really
can't be done with HTML, such as a twitch game, you may be OK leaving it. However, you should still add some
HTML content to the page to at least describe the game for Google and other viewers who may not be able to
play it. Please don't just leave them with a message saying, "This site requires that you have the latest version
of the Flash player" or, worse yet, a completely blank page. At the very least, tell them why they might want to
download Flash to view your site.