After filtering out automated requests (bots, scrapers, etc.), Yahoo analyzed traffic to their properties and concluded that 0.25% (Brazil) to 2% (USA) of people on the web have JavaScript disabled.
The average hovers around 1.3%.
PEOPLE WITHOUT JAVASCRIPT IN NORTH AMERICA & EUROPE
When 2% of people on the web in North America and Europe have JavaScript turned off they fill
NEW YORK CITY
TWICE
or
THE ENTIRE U.S. STATE OF WISCONSIN
What This Means To You
A potentially significant amount of your prospects doesnt use JavaScript " and you will never know.
If your sites functionality relies on JavaScript youll have no clue just how much business youre missing because people have JavaScript turned off.
Popular web analytics tools like Google Analytics rely 100% on JavaScript: they only track people with JavaScript enabled
Your ROI Formula
The return on investment of making your site (also) work without JavaScript is:
(visitors x .02 no JavaScript x % of conversions x avg. sale x avg. profit) " investment
______________________________________________________________________________
investment
For example, if your site has 10.000 visitors per month then there are probably about 200 visitors without JavaScript. A median cross-industry conversion rate is 2.15. So, 2.15% of 200 is 4.3. If your average sale is $60 with a 50% profit margin then youre looking at $120 profit, tabulated over a year makes $1440.
The investment in making your site (also) work without JavaScript depends. If you put it as a requirement in the specs for your next design theres basically no cost as doing unobtrusive JavaScript design (that is JavaScript that leaves your site 100% functional if a visitor has JavaScript disabled) doesnt cost more than doing old-school JavaScript design. On the other hand if you want an issue fixed now then it depends on how complicated fixing that issue is.