I need to do some changes in my HTML file based on whether it is opened in browser or Some Desktop Application.
Till now I've tried this in my script:
alert(navigator.appName);
alert(navigator.appCodeName);
alert(navigator.platform);
But the values are coming same whether the HTML file is opened in browser or some application Software.
How can i set a variable which toggle its value from 0 to 1 when opened in application Software and vice versa.
PS: Application Software like Matlab, MS Office , Britanica Encyclopedia etc.
Short answer, you can't.
Longer answer, to some extent. What you need to do is make a list of differences in each desktop apps implementation, based on known flaws, missing/existing properties, user agent flavours and so on (some of this called "browser spoofing"), to be able to sort them out. It will still be possible to trick this if one want to though.
Normally there is another way of dealing with the differences, the question is what is the different behaviour you want between the 2?
As a sample, and if you still need/insists to detect this, there is device detection libraries which can help as a start, like https://51degrees.com/device-detection
I still recommend to find another way to solve it.
UPDATE
As it is easy to create a desktop app and return the values needed for your page to believe it is a normal browser, I think the best solution is to ask the user on first page hit if they are on a normal browser or not (the one who is not will normally know) and then store in a cookie/set a flag and act upon what the user selected.
I mean it is easy to cheat your page either way so better trust on user selection.
You can use 2 step verification for such cases as devices are getting quite varied. First you can detect devices by media queries strings using innerWidth property. And then you can apply second filter matched by protocol it supports.
Secondly, this SO question might help Frame Buster Buster ... buster code needed
I'd like to be able to make the JavaScript I've got in a web page behave differently by doing something or setting something externally. So there'll be logic checking if(something) execute functionality one, else execute functionality two. I can think of three ways of doing this, but I don't like any of them enough to choose it. At least not unless I can see if there's another blindingly obvious way of doing it that's somehow escaping me at the moment.
Add a harmless query string to the URL (e.g. ?choose_functionality_one=true) and my logic can simply look in the page URL. The reason I don't like this is the case where my code is running inside a cross-domain iframe and I can't even access the page's URL (only the iframe's URL). Yes I could pass the query string to the iframe, but only if I have control over the parent page, and I don't.
Create a cookie in the domain of the page, and my logic can simply look for it in document.cookie. This could be done with a bookmarklet easily enough, and wouldn't suffer from the cross-domain problem, because I simply open a window/tab to the domain where my code is running and run the bookmarklet in that context. This is my front-runner choice at the moment.
Add something to the browser's useragent string and look for that in my logic. Pretty easy on Firefox via about:config, but is less easy with the other browsers, and downright difficult on the Mac. Also, on some browsers, once you've set a custom value, you lose the ability to have the UA get auto-updated when you get a browser update. Your UA's version info is stuck in time to where it was when you first custom'ed it.
Can anyone think of another way that via email/IM/phone I can say to someone "do this" and they'll see the page behave differently for troubleshooting purposes. For the general population who haven't done that though, it's running completely normally.
The simplest option seems to be to make a debug page on your site that will let the user turn the "debug" cookie on/off and then queue your regular site code off the existence of the cookie. I'd suggest making the debug cookie expire in a fairly short amount of time so people don't inadvertently leave it on.
This option has the advantages you are interested in (no user agent modification, works on all platforms, works with iframes) and I can see no disadvantages except that it wouldn't work if someone had cookies off, though a lot of the web won't work without cookies these days so that seems like something you could live with.
In addition, it's also the simplest for your users to use. You can just direct them to the right page on your site and all they have to do is click the desired button to turn it on or off. You can make the page very self explanatory which is certainly much easier than any of the other options.
OK, if you only control code and no HTML, then you could do either implement a keyboard shortcut key that would enable the debug mode by setting the cookie. The instructions could be something like this: put the keyboard focus in X and then press Ctrl-D.
Or, you could implement some special type of click (like a Ctrl-click on some object or in some page corner). In this case the instructions could be something like: Hold down the Ctrl-key and click on object X on the page.
Your JS code could implement either of those shortcuts. You could even put up a prompt (all with dynamically created HTML objects) when the special key/click was engaged to confirm turning the debug mode on or off.
Firefox has the Sandbox and evalInSandbox(). Chrome has sandboxed execution in their content scripts (they call it isolated execution). I'm looking for the same thing in an IE browser extension.
I can load a javascript file, then call evalScript(), but the code executes in the same environment as javascript that exists on the page. I need a way to run my library (which includes and is based on jQuery) in an sandboxed/isolated environment, but still allow it to modify the DOM as if it were running on the page.
Jint looks promising, but cannot currently evaluate jQuery. (They can parse it.)
How can I do this?
Looks like you are in a pickle with this one.
Some Microsoft people say that IE doesn't offer this functionality
Some who say they have been able to pull this off hold it close and protect it as their secret sauce
"Professional" IE extension shops, when contacted about building what you are talking about turn down the job
I really wish I had better news but it looks like it might take a small miracle to accomplish what you are looking for... or maybe a lot of money. : )
Your best bet is probably going to be finding one of the few who claim they have been able to do it and pay them a lot to share the secret or reconsider why you really want what you want and see if you can't accomplish it another way.
You might find it worthwhile looking at the Microsoft Web Sandbox at the Live Labs:
http://websandbox.livelabs.com/
Although it's more fully fledged and related to mashups and the like it might point you in the right direction.
Thing you are looking for is ActiveScript engine (http://en.wikipedia.org/wiki/Active_Scripting)
I can`t find any usefull links now, MSDN contains only interfaces definition (http://msdn.microsoft.com/en-us/library/ccd0zt2w(v=vs.85).aspx)
Try to Google "Active Scripting" (not "Action scripting"!)
You need to implement interface IActiveScriptHost in your extension, create an object of «JScript», call SetSite and pass your host object, then you can load your js code into this engine and run it.
This technique is a quite difficult due to lack of documentation about it.
If you are still interested in this, I can send you some examples in C++/ATL.
Can you elaborate on your goals a bit?
I don't think you've clearly defined what you're trying to accomplish. If your code has the ability to modify the page's DOM, then it effectively is executing in the context of the page. It can create new script blocks to perform any unsafe or unreliable action that it could accomplish were it operating in the same execution environment.
IE doesn't offer a feature to do what you're asking, and I'm not convinced that the Firefox and Chrome features work the way that you expect that they do.
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'm thinking this might be a quick and easy way to lower the form spam on our site just a little bit. The idea being that (I have read) spammers aren't running with javascript enabled. (Or at least they are accessing your website without running javascript. I.e., they aren't browsing up to it in IE or FF.
I can use .asp or .aspx.
The simplest way is to set a cookie via javascript and check for it on postback.However, if you're looking to minimize spam you should actually have the browser perform a simple task which requires javascript execution. See Phil Haack's "Invisibile Captcha Validator" control, which has since been included in his Subkismet library: http://haacked.com/archive/2006/09/26/Lightweight_Invisible_CAPTCHA_Validator_Control.aspx
In .net, you can use Request.Browser.JavaScript to detect if the browser supports JavaScript. However, the user may still have Javascript disabled. An ugly way to check to see if Javascript is enabled, is to use window.location to redirect to page.aspx?jscript=true, and then check Request.Querystring for that value.
So, you want to force users to use JavaScript in order to use your site? I'd rather just use a simple Captcha. If you aren't a big-name site, you can get away with some relatively simple Captchas.
That's how we reduced spam at our site.
To be honest, you shouldn't need to use a server-side language to detect javascript, and furthermore spammers are not necessarily not running javascript. (sorry about the double-negative) Your objective is good, but your approach is wrong - implementing a CAPTCHA, as suggested by a few of our peers, would be a great way to handle this.
I see you've accepted the noscript answer, but how will you use this to fight spam? noscript will allow you to add special content for users without JS, but unless you're generating the rest of your site in JS, it will still be available to user agents without JS.
A captcha of some sort is still likely the best bet. Ultimately, you're trying to get the user agent to prove that it's being controlled by a human, so do your best to make it prove that actual fact, instead of something else. Screen readers for the visually impaired typically go without Javascript, too, and many people browsing from mobile devices have Javascript disabled to speed things up.