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Years ago I used to design with JavaScript disabled browsers in mind. How important is it nowadays?
Is it really something you need to worry about? I've never come across a user in real life who has JavaScript disabled. Anyone got any figures?
Having had my own company for a year and working at another for a couple of years, none of my direct clients has ever had JavaScript disabled, in one single instance I've had one of my clients customers have JavaScript disabled, so my current guess (purely anecdotal evidence) is about 1/50.000.
My biggest worry when working with JavaScript is and has always been cross browser compliance, what works in FF doesn't always work in Chrome, what works in FF and Chrome doesn't always work in IE 8, and what works in all of the above... doesn't always work in IE 7.....
And then there is IE 6.
Edit, yay data:
By July 31, 2009 firefox had 1 billion downloads
Noscript has as of September 14, 2010 73 million downloads
That tells us that about 7% of the times FF users has downloaded the browser, they have also installed the noscript plugin.
Edit addendum
Making this community wiki, add your math people.
Edit:
In October 2010, Yahoo! published actual stats.
In short, the answer varies by country, but for a US site, you can expect 2% of your users to have javascript disabled.
My tips would be:
Designing a site with a fallback to no JS is usually entirely possible and not all that difficult. You should consider doing it, regardless of what the statistics about JS-disabled browsers say.
However, don't let this stop you from being creative. If you must rely on JS and there's no workaround, don't hesitate. If someone wants full browsing experience and works with JS off, it's his/her fault.
Encoding emails using JS unescape() is always a good idea. In a JS-disabled browser, just display nothing.
You're right: straight up disabling of Javascript is pretty uncommon these days because it is used by so many sites.
However most browsers have more fine-tuned control; ie to turn it on/off per site, which may still be used by paranoid.. uh, security-conscious users.
Even more likely, there's a Firefox extension called NoScript which is actually very popular. This extension gives the user even more control over when to allow Javascript. I don't know whether there's similar plug-ins for other browsers, but I expect so.
Finally, many disabled users will be running screen-readers or other accessibility browsers which may still not run Javascript properly/at all. If you want to support these users, then you'll need to be aware of the unique environments they work in.
So yes, it is still a good idea to support non-JS users, even if they are in the minority. That said, I don't think you need to make everything work for them, as long as your basic site functionality works (ie add to basket, checkout, etc), there's no need to get too stressed about them not getting the bells and whistles.
The NoScript plugin for Firefox has been downloaded 73,063,406 times.
Your site should be usable without JS (so don't replace links with JS voodoo unless you absolutely have to).
Also people that need special output devices (like Braille Readers) will prefer sites that that work without JS.
I agree that disabling javascript is uncommon and i also agree that it's important to build websites while taking javascript-disabled browsers in mind.
BUT javascript is strongly invloved in modern & large websites now (google, youtube, facebook). without javascript you can't build AJAX supported websites and you can't also use the power of jQuery or any js library.
and if you are worry about cross browser compliance, you might wanna consider using jQuery because it abstracts away the famous cross-browser issue.
personally, i'll be always using javascript in any website i build :).
I'm a bit late to the party, but about a month after this question was asked, Yahoo! published actual stats.
In short, it depends on where your visitors are from, but in the US, you can plan on about 2% of your visitors having javascript disabled.
Here's a couple of general guidelines. People who use different browsers with accessibility in mind, or run in a terminal with no graphics toolkit (text based) are most likely to not run JavaScript. If you want to cater to these people, all you need to do is use JavaScript if you want, but only use it to enhance, not provide the content.
By this, I mean, for example, you can enhance a table by adding sort controls with JavaScript, but don't use JavaScript to parse a data file and create the table. Use a server-side program to handle a database or data file instead.
However, there becomes a grey area, and this all has to do with what kind of user base you are targeting. If you are writing a Chrome experiment then by all means, write it all in JavaScript; it's about the JavaScript.
If, however, your website aims to provide information, it's best to avoid using JavaScript to provide content wherever possible; only enhance it.
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I hear about it a bit in tutorials that I watch, that certain things won't work if javascript is disabled. Occasionally I see workarounds.
The question is, are these relevent? I can't imagine anyone not having a javascript enabled browser nowadays, except the most ancient of phones, and chances are your page won't render on them properly anyway.
Do people still bother to write backup code for javascript being disabled?
Edit: As a test, I turned javascript off. Facebook doesn't work.
Edit: I understand about visually impaired users, but do people care (harsh, yes) if their experience is buggy? Not to sound disrespectful, but not sticking to strict standards will alienate people using Internet Explorer 4 and 5 too, but we don't seem to care about them...?
Edit: Saying that people should do it seems like a very automatic response, considering how many people use JQuery and other groovy addon libraries.
Edit: I tried a bunch of fortune 500 sites, and so far about 70% of the ones I tried have broken
Dell
Walmart
Fedex
Intel
Coca Cola
Yes, we still need backup code for people who have JavaScript disabled.
JavaScript is often used to do things that break in screen readers (so many screen reader users disable it) or to cause changes to appear out of sight of a screen magnifier.
JavaScript is still one of the biggest attack vectors to exploit security holes in browsers.
Add-ons such as No-Script are increasing in popularity.
Search engines tend not to execute it (so you don't want to hide your content behind it)
I prefer to think of it as a foundation rather than backup.
I understand about visually impaired users, but do people care (harsh, yes) if their experience is buggy?
Nasty people don't.
The law (in many jurisdictions) does.
Not to sound disrespectful, but not sticking to strict standards will alienate people using Internet Explorer 4 and 5 too, but we don't seem to care about them...?
IE 4/5 have:
a smaller market share than users without JS
many security holes
no support from their own publisher
As a developer I no longer worry about 1% of users who turn off Javascript. It is too time consuming and development time is too expensive to waste on such nonsense. AJAX saves an incredible amount of bandwidth which turns directly into $$$ savings, which makes profits higher. If I lose one or two potential users of the site for every 100 users, those one or two lost users will cost a lot more in development than the potential income of they could ever bring in.
Try turning off Javascript and logging into Facebook, it becomes a very broken website after that. If it's good enough for Facebook, its good enough for me.
Support for JavaScript-disabled web sites a nice thought, but not of much help, and of questionable value, IMHO
It is almost impossible to design a robust website without java script, and those that disable JS, for whatever reason, probably don't expect much of a user experience. So if you are coding for that 1% of the population, you have no choice. But for the majority of us, it is a given that JS is there. Accessibility is a different issue, with its own challenges. When I was doing web sites for Hewlett-Packard, they had to meet strict accessibility standards, and it was tough to create anything more than very basic web pages. I wouldn't wish that on anybody.
I have a different opinion to many here. I don't think you necessarily should care in some scenarios, especially if your website is targeting a particular group of people or that it is going to mean a lot of work.
if you refer to:
http://visualrevenue.com/blog/2007/08/eu-and-us-javascript-disabled-index.html
(source: visualrevenue.com)
You can see that year on year more browsers than ever have Javascript enabled, contrary to the other answers' claims. It was at 96.9% in 2007.
So you lose 3% of potential viewers, so what, your advertising campaign will do a lot more damage than that!
Yes. Especially when it comes to 508 and WCAG compliance. While the technologies to create accessible JavaScript are coming out of their infancy (see ARIA), developer's should still be coding sites in a way the does not require JavaScript.
http://www.w3.org/WAI/aria/faq
http://www.w3.org/TR/WCAG10/
All the other questions got most of the points covered, but I'll chime in with this: it's not a big deal to have your page(s) degrade gracefully in the absence of javascript. If you've got some super-whizzy ajax-infested real-time comet style app that really isn't going to work without javascript, you should at least render a nice message to the effect that javascript is required.
It depends on your audience and type of website.
For instance, a graphic artist portfolio will not be visited by blind people or people using text browsers. So in that case it's not so important to build nice degradable JS, expecially because it will most probably be used for graphic effects.
If, on the other hand you're developing a news website and you decide (for whatever reason) to dynamically load your news with JS then you should definitely make it degradable. Also, remember that the spiders of indexing engines may have difficulties in indexing content loaded with JS in your page.
At the end of the day, in most cases it's not so difficult to program the site so that it works without JS. If you're retrieving content dynamically you already have the server-side code to load the content, you just need to accomodate how the page is called.
Same thing for forms, you can send the content via AJAX or via a normal POST, the backend will be pretty much the same, so it's again easy to implement.
Of course, the problem is not even posed for JS code that is purely graphical.
My recent experience:
My former supervisor claimed, in earnest, that because Google Analytics told us that "87% of our users have Java enabled and less than 3% are using IE6," that we didn't have to worry about supporting older browsers or users with JavaScript disabled.
Problem 1: Java is not JavaScript.
Problem 2: In order for Google Analytics to track a hit, the browser must have JavaScript enabled because the GA interface is a JS include. GA is not, and can not, be aware of users with JS disabled, which can potentially severely skew its reports.
Problem 3: one of our biggest customers requires that all engineers use IE6 with JS disabled.
Problem 4: The boss (at the time) didn't know how to read analytics reports.
If you want to know how important this support is to your business, a good place to start is the IIS logs. Just about everything related to the browser caps is stored by IIS. I regularly import the logs into SQL Server and run some basic reports from my admin site, which come in handy every time someone starts suggesting that we go crazy with the jQuery BS.
If you decide to start building complicated, script-dependent interfaces, be sure that your interface degrades gracefully and doesn't remove required functionality if JS is disabled.
It is not merely a question of whether a browser is capable of executing javascript, but if a user has disabled it for some reason.
For example, you need to be aware of vison-impaired users. Such users might disable javascript, because the effects are confusing their screen reader software.
I'm currently building a project and I would like to make use of some simple javascript - I know some people have it disabled to prevent XSS and other things. Should I...
a) Use the simple javascript, those users with it disabled are missing out
b) Don't use the simple javascript, users with it enabled have to click a little more
c) Code both javascript-enabled and javascript-disabled functionality
I'm not really sure as the web is always changing, what do you recommend?
Degrade gracefully - make sure the site works without JavaScript, then add bells and whistles for those with JavaScript enabled.
Everyone else has committed good comments, but there are a few other considerations to make.
Sometimes the javascript will be hosted on a different domain, and be prone to timeout.
Sometimes that domain may become inacessible, while your site remains accessible. Its not good to have your site completely stack itself in this scenario.
For this reason, "blocking" scripts ( ie: document write inline ) like that present in google's tracker, should be avoided, or at very least, should go as late in the page as possible so the page renders whether or not the domain is timing out requests or not.
If you happen to be serving JS from a broken/malicious server, by intent or by accident, one can halt page rendering simply by having a script that serves that javascript which just calls "sleep(forever)" once its sent all the headers.
Some People Use NoScript
Like the above problem, sometimes the clients environment may block certain script sources, be it the users choosing, or other reasons ( ie: browser security satisfactions, odd antivirus/anti-malware apps ). The most popular and controllable instance of this is NoScript, and I myself paranoidly block some of the popular tracking/advertising services with it ( some proxy servers will do this too ).
However, if a site is not well designed, the failing of one script to load still executes code that was dependant on that script being present, which yeilds errors and stops everything working.
My recommendation is :
Use Firebug
Use NoScript and block out everything --> See Site still works
Enable core site scripts that you cant' do without for anything --> See site still works and firebug doesn't whine.
Enable 3rd party stuff --> See site still works and firebug doesn't whine.
There are a lot of other complications that can crop up, but satisfying the above 2 should solve most of them. Just assume that, for whatever reason, one or more resources that comprise a page are viable to spontaneously disappear ( they do, all the time ), and you want the page to "survive" this problem as amicably as possible. For the problems that may persist for < 10 seconds, its not so bad, refresh the page and its fixed, but if its a problem that can occur, and severley hamper usability for an hour or more at a time.
In essence, instead of thinking "oh, theres the edge case users that don't have javascript", try thinking more a long the lines of "its really easy to have something go wrong, and have ALL of our users with broken javascript. Ouch! Lets try make it so we dont' really hose ourself when that does happen"
( I've seen IE updates get rolled out and hose javascript for that entire browser until the people whom wrote the scripts find a workaround. Losing all your IE customers is not a good thing )
:set sarcasm
:set ignoreSpelling
:set iq=76
Don't worry, its only a 5% Niché Market
Nobody cares about targeting Niché markets right? All those funny propeller heads running lynx in their geeky stupid linoox cpus, spending all their time on the intarwebs surfing because they have nothing better to do with their life or money? the crazy security paranoid nerds disabling javascript left and right because they don't like it?
Nobody wants them as your primary customer now do they?
Niché markets. Pfft. Who cares!
:set nosarcasm
Consider your audience
"Degrade gracefully" is generally the best answer. But lots of sites now depend on JS - especially AJAX.
Consider your audience. If your site is aimed at extremely tech-savvy people, the chances of them not having javascript are small, and you can notify them to turn it on if necessary.
If your audience may access your site with mobile devices, don't assume they have JavaScript, and don't even assume they support CSS properly. Aim to degrade gracefully all the way down to bare HTML.
I've learned a lot from my question: What's With Those Do-Not-Use Javascript People
Go with Ajax and Web 2.0. It's the way the web is going and it's wonderful. Isn't Stackoverflow great to be on? It's not quite as nice with your Javascript turned off.
Once you have your site ready, but before you let it go live, test it with Javascript off, and just add whatever you feel you need to make your site appear and function to them. You only need to add what you feel is essential.
Remember, except for visually impared people using screen readers, the others have chosen to turn javascript off. They can also choose to trust your site and turn javascript on for your site if they want to use all the functionality you have. It really is their choice.
As other have said, it should "degrade gracefully".
In other works, it must work without Javascript (period). It doesn't have to work well. The folks who've disabled Javascript know the limitations that causes and have accepted them. But if you are trying to sell them something, it's important that they can still buy it.
On the site I'm designing, there's a javascript-based fly-out menu. With Javascript off, all the flyouts are always open. It doesn't look as cool as it would with JS, but it can still be used to navigate the site.
It depends on how much time you have to develop and maintain both solutions, and how much the non-javascript users are worth to you.
My e-commerce site relies heavily on javascript, and in over a year and a half, I've not received a single complaint.
In fact, I don't think I've seen a single visitor with javascript disabled in any of logs since I started.
That doesn't mean they're not out there. It just means that either (a) they're a tiny percentage, (b) they're not interested in what I'm selling, or (c) both of the above.
Code your web site with support for the bare minimum kind of browser. Then more people can use your site without frustration even if they don't have all the bells and whistles--like Flash, Javascript, and Java--enabled. It may not be practical to continue support for ancient browsers, say Netscape Navigator 4, because a user can be reasonably expected to keep their computer up-to-date. However, features like Javascript, Flash, and Java can be security holes in old or modern browsers, as well as being an annoyance.
Neither of my parents keep Javascript or Flash enabled because they've had too many experiences with them slowing down their already slow connection, crashing their browsers, or being more of an annoyance on sites that use it stupidly (which is a lot of them...) than a useful feature. It's just bad design if, for example, your form requires an AJAX call be made and you can't actually hit a submit button to send the form when Javascript is disabled.
My mother was recently quite frustrated to discover that she is now unable to click through eBay results pages because each one requires Javascript. The only way she can see the next page of results is to turn on Javascript or to show more results per page. Now what reason would there be for page links to require Javascript while the 'results per page' links are just plain links? They should all be plain old HTML links. Maybe Javascript could be used to add some whiz-bang to the navigation, but a user should not be punished with a bad interface for having Javascript disabled. It's stupid on eBay's part, and it causes undue hassle for their users.
I am one of those that uses 'No-Script.' And I can tell you that sites that use javascript and don't work without it enabled is extremely annoying, stackOverflow... No we don't expect it to be very fancy, if I upvote load a new page that says "Thank you."
We expect to be able to use the site with reasonable limitations, don't ever display a page that says JS must be enabled, though, even if the site is crap without it. And yes if your site convinces us to stay we will enable. A function that isn't in common use on the site can also require javascript.
Please note that your site should also look good with no JS or CSS, if nothing else it is good for Bots.
As others have pointed out some phones don't have JS, this is changing but another good reason to have reasonable non-JS. I suggest code with non-JS and add JS after the former works, there are good ways where JS can work with the non-JS layout.
It helps me in my implementations to think about it as "progressive enhancement" rather than graceful degradation. Degradation often leads you to figure out how to make it work w/o js after it is implemented, instead of making a baseline and enhancing with js.
It is essential to at least test your website is functional when JavaScript is turned off.
As orip says, degrading gracefully is very important. It should be vital that your page both looks nice and functions when JavaScript is disabled.
For a standard web site that is primarily intended for conveying information, degrade gracefully always.
For web applications:
When building a web application for a standard internet audience, I would keep the three following facts in mind:
95%-97% of potential users will have JavaScript enabled.
At times established users will need to access functionality when JavaScript is not available.
3%-5% of potential users will have JavaScript intentionally disabled.
Given fact one, if you believe that building a JavaScript reliant web application will deliver a superior user experience, then by all means do it. Doing so may help you accumulate users.
However, given fact two, you should always provide a means by which your users can access core functionality without JavaScript. Do you need to offer every single feature? Probably not. But a user should be able to get his or her work done. This will keep your users happy when they find themselves temporarily without JavaScript.
Given fact three, I would also provide an in depth tour as an attempt to entice these users to enable JavaScript.
As an aside, one of my most favorite web applications, Remember The Milk follows this approach. Also, Google's Calendar application is unusable without JavaScript. So JavaScript reliant web apps are on the rise and that trend is probably unstoppable. In my opinion this is a good thing.
(Do keep in mind that JavaScript make Accessbility a bigger problem than it is already. Please do make an effort to make your apps usable by those with disabilities.)
As said before, it depends on your target audience.
If I'm part of it, you want to make sure that your site works (if not ideally) on my phone, and that it gives me reason to turn Javascript on when I surf there with it off. Nobody expects full functionality with Javascript disabled, and anybody who uses their phone to access websites expects some issues, but you need to at least provide teasers. For a web store, make sure customers can see at least some merchandise anyway, even if they can't buy without Javascript.
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?
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.
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."
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.
http://www.w3schools.com/browsers/browsers_stats.asp
They claim 95% of users have Javascript on.
Duplicate
There's at least one category where the answer is definitely "no". If you work for the government, you must make sure the site is accessible to those using screen readers.
Is it reasonable to assume visitors
have javascript enabled and simply
have an unusable site for those who
don't?
There are actually two questions, and the answers are: Yes, it is reasonable to assume visitors have javascript enabled. And, No this does not mean others should be left with unusable site.
Progressive enhancement is the way to go. Have your site usable without javascript and then add bells and whistles.
As for client side validation, it is no more than a convenience for user to avoid unnecessary roundtrips to server (where real validation should be performed).
I browse with the NoScript plugin in firefox and I'm surprised at the amount of developers that haven't even considered making their site degradable.
Never assume the user has JavaScript disabled - especially seeing as it may not always be their fault. Many enterprises have firewalls which block JavaScript/ActiveX etc. - In this instance the <noscript> element won't work so I would NOT recomend using that either!
Unless you're creating a full-on web application which is going to be 90% Ajax then you must make sure to abide by standards and progressively enhance your site through various layers of interactivity.
Also don't forget the important of object detection, especially with the rise of mobile phone web browsing. One of the most popular mobile web browsers (Opera mini 4.0) doesn't allow all "Background javaScript" to work and Ajax calls rarely execute correctly... Just something to be aware of.
To be honest I am sick and tired of developers that think everyone will have JS enabled! What ignorance!!
Yes it is. But expose as much of it as possible through regular HTML and URLs, if for nothing else than for Google.
Accessible, yes... functional? Not really.
This is really a customer requirement question more than developer-answerable, but if your customer tries to enforce a requirement that non-JS browsers work, you should argue heavily against it and really hammer them on the "cool" factor they'll be missing.
Given the heavy reliance by GWT, RichFaces, etc. on Javascript, it's just not feasible to make an app with any kind of user-friendly UI without it.
You should certainly warn non-JS enabled users that the site they're trying to visit relies heavily on JS, though. No point in being rude about it.
It is ok in these days to assume your visitors have JS enabled. With that said, you should strive for the best possible degradation of your site with JS disabled. It is ideal if your site falls back to a state that is still usable without JS.
No! Some environments will have it disabled as a matter of policy, with nothing you can do to enable it. And even if it's enabled, it might be crippled.
This question has been asked before.
One interesting point to consider is that as a web developer you have a social responsibility to push technology forward - and by using things like AJAX, you increase exposure and potentially rate of adoption along with it. The only thing that should stop you from using the tech to its fullest extent is money - if you won't make the money that you need because people will have trouble viewing the material, you've got to reconsider.
Never ever assume Javascript for form validation, as your question implies. Someone will eventually realise this and turn Javascript off.
Instead, code the app in fairly regular html manner and use Javascript for what it is: an optional perk for your users.
Even for an entirely AJAX app like Gmail, the complete works of form validation is required on the server side.
Yes it is, JavaScript is as old as CSS and no one tries to build around browsers that don't support CSS. Cross Site Scripting is the reason people are afraid of JavaScript, but believe me if a developer wants to screw you over he doesn't need JavaScript to do it. As far as mobile browsers, most of them now have JavaScript, and the others shouldn't be considered browsers. My advice is not to open yourself to hackers by making your site vulnerable to those who choose to turn off their JavaScript, but at the same time don't go out of the way to support those who are living in the stone age. You aren't going to support IE 4 or Netscape, right? Then why support those who sabotage their own browsers because of blatant fear or paranoia?
I think it's fair to assume that the majority of visitors to your site will have JavaScript enabled. Some of the more trafficked sites out there have a dependency on JavaScript. For example, I was surprised to learn that you can't authenticate through a Passport-enabled site without a JS-enabled browser.
Nearly all (but not quite all!) users will have javascript enabled. (I believe the figure quoted above of about 5% is accurate.)
Given the vast improvement in usability you can make with the judicious use of javascript, my opinion is that most of the time, it is reasonable to assume it is enabled.
There will of course be some instances where that is not the case, (ie, a site designed for mobile devices, or with a high percentage of disabled users etc), and always a effort should definitely be given to making your site as accessible as possible to as large a percentage of the population as possible.
That said, if you only have a low traffic site, 5% of a small number is a very small number. It may not be worth bending over backwards to make your site accessible to these people when it may only gain you one or two extra users.
I guess the short answer is (as always), there is no correct answer - it will depend entirely on the target use, and target users of the sit in question.
According to this little page Javascript is enabled in 95% of browsers and it keeps raising.
The W3C Browser Statistics page (scroll down) has some information on this; they say that 95% of visitors have JavaScript on as of January 2008.
It's reasonable to assume your visitors have javascript enabled !-)
-- but of course it depends on who you're trying to reach ...
Several times above w3schools have been mentioned and, as Dan stated, its their own visitors which make it somewhat quirky to draw conclusion from.
However, if you look at theCounter.com it seems that their audience has the same habits in general on this point ...
A twist that hasn't been mentioned yet is the growing amount of crawlers, mailharvesters and so on, they definitely do not have javascript turned on, and how good are counters to detect them ?-)
My guess would be, that this sort of machine-browsers fill up a lot of those 5-6% !o]
-- that said, if it's at all possible, make your app degrade gracefully (as a wise man said)
Your questions seems to suggest form based input for an application. If it's an intranet application then you'd be guided by the in-house security experts. If it's public app, then as other posters have suggested, fail gracefully.
I will argue that it is more than reasonable to expect them to have javascript so long as you provide suitable means to replace javascript should it not be enabled. One of the reasons that I like the Yahoo UI Library is that it degrades gracefully.
I always try to code my sites as static one first, THEN i add js/ajax functionality. This way i can be kinda sure that will work on non JS browsers :)
But, javascript is like flash: all users have it, but developer have to concern on WHAT IF.... ? :D
No its not, period, full-stop, end of story. Its just naive and wrong at an ethical level, not to mention you miss out on around 50% of Internet users worldwide (believe it or not 70% of web access worldwide is from mobile devices).
Add extra nifty stuff that requires Javascript, thats fine. Don't make your site unusable without Javascript unless you have really, really, really good reason to do so.
Someone rightly pointed out that I don't have evidence to back up my claim of 70% mobile web users. Unforunately I can't find the source I got it from but I remember it being authorative so have no reason to doubt it. It does make sense though when you consider worldwide usage, many developing countries have more mobile phones than landlines and broadband. A statistic that was quoted in my not-to-be-found source was that one African country in particular has 300,000 landlines, but has 1.5 million mobile phones!
This is totally a "it depends" question, as many people have pointed out.
This is why metrics is valuable on sites to help show if you can really run with the analogy that "major sites say that the majority of people have JS on" - you could have a site where it's 99%.
I won't dig in to what's been said above, as it's been answered very well :)
Not that everyone else hasn't chimed in, but I disagree with the "look at your audience" position to some extent.
It really should be "look at your app" if you are just displaying some information, and your js is for bell/whistle purposes, then certainly look at nice degradation, if you want to.
However, if you're building something like Google Docs, it's really asinine that someone would think they could use your site without js, so perhaps let them know that via a nice sarcastic message inside <noscript> tags.
From a purely philosophical point of view, if users want to access your site, they will flip the js switch, or upgrade to a decent browser, etc. And you should force them to do this, because evolution is important for the survival of the species.
According to this site, 95% of browsers use JavaScript.
That said, there are a LOT of bots that don't use JavaScript: scrapers, search bots, etc. I'd say closer to 100% of actual human users use JavaScript. But your guess is just as good as mine.
Is it alright to expect that the user using the back end will have Javascript enabled?
I guess the answer I'll get is 'it depends on your target users'. I am developing a system for fun that will hopefully be used by other people. I would like to hear from other people developing back end systems, and what did they decide to do and why?
SEO I'm not concerned with, and semantics aern't of as much importance.
Personally I would expect the failover, but there are circumstances (particularly low profile sites, intranets, e-learning content) where you can assume JS.
Mostly you can even go with a simple "You require JS / This works better with JS" and I would consider that good enough, but there's a couple of instances where I would demand real failover:
.gov or other public service sites (legal requirements)
sites for web-tech companies (you need to demonstrate your ability to do this)
very high traffic sites (where the 3% of non-JS users becomes a high absolute number)
sites (or pages) for mobile devices (most of these haven't got JS reliably)
In general, it's reasonably easy to provide some kind of noscript, so why not do it anyway?
if its for fun please go ahead and require javascript.
considering the 3 points :
backend means only a few people will be accessing them (and all of them probably have knowledge about web too, eg. know what javascript is and how to get it enabled)
SEO isn't important
it's for fun
I'd say that it's alright. :)
annakata provided a pretty good insight as well.
It really depends on your application and its target audiences. Do you care about user accessibility (can disabled people use the site), do you want your site to work on various mobile browsers with limited JavaScript support? I would try to build the site so that it would gracefully degrade without CSS or JavaScript. That is unless you site is very dynamic, like say a word processor which can't possible work at all without JavaScript.
Yes, It mostly depends on your target user.
Whatever the front end is, the back end must be bulletproof.
At least, it should make ensure that, nobody can hack or make a mess by disabling javascript.
server-side filtering/validations is important for security, while client-side validation and interactivity is important for usability.
I don't think it's unreasonable to require Javascript for a web based backend/CMS, where your target users are likely to be a fairly small and pretty specific group.
All the CMS systems that I've worked on so far have required it.
I refer you to this post by Jeff Atwood. The important assertion in it is that you can expect that javascript will work as expected among browsers. The security risks are also lower today. So I would say that is now safe to ignore clients that do not enable javascript. If you want to attack users javascript would give a clear advantage.
The only exception I can think of is mobile sites. Although mobile browsers have gone better and do support javascript, the extra download bandwidth and the small screen make js less suitable.
As long as the function that your application will be serving is general, I'd say it is safe to rely on Javascript. One of the sites that I manage receives ~35,000 UV's on a good day. I think it is fair to say we come in contact with quite a variety of browser and operating system combinations. According to our stats, roughly 97% of our users have Javascript enabled.
If it can fail elegantly without Javascript, I'd opt for that solution, but I wouldn't lose sleep over the fact that you might be losing a few people everyday.