There are good reasons to insist that developers take extra time to make Web sites accessible-such as enabling it for the screen readers that blind users need-not the least of which is ADA legislation. But who's paying attention to making a site run well without JavaScript? It might be more necessary than you imagine.

For the last several weeks, I've been living in the future. I interviewed some of the smartest people around about where the world of Web development is headed, much of which centers around "Web 2.0" - which means AJAX, which means JavaScript.

Concurrently, my spouse just launched his client's Web site for a specialty bookstore. He took the time to ensure that its e-commerce system worked even when JavaScript is disabled. It's ugly, he says, but it works. However, he was astounded to see that, in its first week, about 40% (yes, 40%!) of people buying mystery books online (such as a first edition of Diana Gabaldon's Outlander or a signed copy of Joe Garagiola's Just Play Ball) make the purchase with JavaScript turned off.

Is this common? We spent some time puttering through popular sites to see how well they worked with with the feature disabled in the browser, and as expected most of the sites are ugly, lose functionality, or are essentially useless. (CIO.com is better than some, worse than others. But you won't be able to reply to this message unless you turn JavaScript back on.) Yet-as I wrote in that Beyond Ajax set of articles-the world is poised to use more JavaScript, not less. Do you see a problem here?

Before you rush to examine your own site statistics, look at how those metrics are gathered. Your site may not know about the visitors who have turned off JavaScript, giving you questionable numbers (I'm not quite certain of that; I'm sure the SEO techies will clarify for me) and moreover giving you the idea that everybody is using JavaScript when that's not the case.

For example, the Google Analytics UrchinTracker uses JavaScript to collect customer data, using a combination of server and client-side technology including cookies. It promises to let you track events on your site that do not generate a pageview. "Using the urchinTracker JavaScript, you can assign a specific page filename to Flash events, JavaScript events, file downloads, outbound links, and more," they say. The site tracking software we use for CIO.com said that 100% of our visitors use JavaScript; and although it did log our experimental visit (100% minus 1), I'm not sure if I believe it.

Essentially: If your tracking data incorrectly implies that all site visitors use JavaScript, you may be coming to the wrong conclusions.

This sidesteps the issue of why someone would turn off JavaScript, and whether they're dumb to do so. Some people see JavaScript as a security hole; others want to block advertising; still others see user tracking as an invasion of privacy. Some companies turn it off as corporate policy. This isn't about whether they should do so; the bottom line is that they do, and what (if any) consequences that has for your Web site development efforts.

Your developers probably hate to invest the time in writing and testing code for the site to make it "play nice" with screen readers and other legally-mandated accessibity/ADA issues. I understand why. Programmers design apps that do what they must, and use the best technology available, and it's time consuming and annoying to have to re-do the work for what's perceived as a small number of users. (Again, we're talking about perception, which may or may not be related to reality.) Do you want to tell them they'll have to re-create the site for the JavaScript shy?

If you're busily designing the next great Web site (such as NASA's, currently in preview), I'd bet that it includes at least some JavaScript elements. How much attention are you giving to the visitors who won't see them? What are you doing about it? I don't have answers here... only questions.