Is it reasonable to assume my visitors have javascript enabled?

I understand that server-side validation is an absolute must to prevent malicious users (or simply users who choose to disable javascript) from bypassing client-side validation. But that's mainly to protect your application, not to provide value for those who are running browsers with javascript disabled. Is it reasonable to assume visitors have javascript enabled and simply have an unusable site for those who don't?

Solution 1:

I browse with NoScript in Firefox, and it always annoys me when I get pages that don't work. That said - know your audience. If you're trying to cater to paranoid computer security professionals - assume they might not have JavaScript enabled. If you're going for a general audience, JavaScript is probably on.

Solution 2:

Totally depends on who you're aiming at.

If your site or app is for an Intranet, you can make lots of assumptions. If your target audience is bleeding-edge social-networking types, you can assume JavaScript will work. If you anticipate a lot of paranoia sysadmin types, you can assume a bunch of them will be trying to access your site in lynx or have JS turned of for "security reasons."

A good example of this is Amazon -- their approach is driven by their business goals. They are a mass-market site, but for them, locking out users in old/incapable browsers means potential lost sales, so they work hard on non-script fallbacks.

So like lots of these kinds of questions, the answer is not just regurgitating what you've read somewhere about accessibility or progressive enhancement. The real answer is "it depends."

Solution 3:

I think there is another reason which push you to support at least some main functionality without JS - lots of us now browsing from mobile and PDA, which have no the same lvl of JavaScript support.