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Different browsers have separate implementation of JavaScript [closed]

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Closed 9 years ago.
I am new to JavaScript. I am referring to a page on JavaScript framework: What is a JavaScript framework?
I know JavaScript is for the web client side. It is a object-oriented script language. The link above writes:
Using JavaScript, however, is not an easy task, primarily due to the complications that arise when trying to provide support for multiple Web browsers.
Like HTML and CSS, different browsers have separate implementations of JavaScript, and it can be a nightmare to ensure that your JavaScript code is cross-browser compatible.
The second part says different browsers has different implementations. Why?
Since JavaScript is just a language like Java, C etc. Why do different browsers need different implementations?
As long as the JavaScript language specification is released, each browser should follow the language requirement. So why they have different implementations?
What does the implementation here mean?
EDIT:
JavaScript is NOT a object-oriented language! It is a language based on objects!

"Implementation" here is the engine that was implemented by a browser vendor according to ECMAScript specification.
As long as the java script language specification is released, each browser should follow the language requirement
And they do
So why they have different implementations?
Because they follow the same specification but build their own engine.

That's just the way it is. Not every browser uses the same JavaScript engine, click the link if you want to read some interesting history.
They all try to be the fastest. And yes they should all follow the exact same specification, and I'm sure they have followed the exact same specification, but there are still people involved, and they might interpret the specification slightly differently.
These engines are being developed in parallel (at the same time), as none of their developers have time to wait for the others to develop something first, and then check to see if they can comply with the exact same interpretation of the specification as their competitors.

JavaScript is an ECMA standard programming language and does not need to run in a browser. The browser has a JavaScript enginge that runs the script for you but not all browsers run it the same way.
Notabley is the way IE and other browsers handle events and new features are sometimes not supported. IE implemented things like innerHTML wich was not ECMA standard but because of it's popularity other browsers adopted it. It might be part of the standard now but I'm not sure.
The reason for this is that when NetScape came with JavaScript support IE implemented it as well but with other (extra) features. Since they both try to compete to be the "better" browser they didn't work together on making a standard.
A good source for JavaScript usage in browsers is MDN It usually shows you browser support for JS methods and properties as well as some code to add some support for browsers that don't support certain features (like DOMParser parsing text/html)
In the last couple of years IE has made a move to be more ECMA complient so hopefully in the future we would have to rely on less and less feature detection in our JavaScript code.
You still have a problem that JavaScript is a still evolving language and more and more features are added. When they are new than browers will still implement it differently or not implement all featueres (like webcrt). You might also have to support browsers that are a couple of years old and a lot of things change in a couple of years.

Using CoffeeScript in a production environment [closed]

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Closed 11 years ago.
I really like using CoffeeScript (1.1.1) for small projects and it worked out great so far. However before using it in a more broad environment I would like to hear second opinions on using it in production.
So my questions are:
How stable is the language itself?
Do I need to watch for upcoming changes which will break my code?
If the answer is yes to the question above: how well are older versions supported?
Is there a stable (bug-fix only) and a separate development branch?
If you already did use CoffeeScript in your product/website/etc please describe the scope in which it was used and your overall experience.
Thanks!
Note: I've already heard that "CoffeeScript support will be included in Ruby on Rails version 3.1." (Wikipedia) which is great because of the additional backing from the Rails community.

The language has been stable for the last six months (1.1.1 is basically just 1.0 with bugfixes). That's no guarantee of future stability, but I don't expect my book to be totally obsolete any time soon.
I'd say the best practices for avoiding version issues are
Make sure you document the version of CoffeeScript that your project was written for, and
Compile to JS under that version and keep the JS stored somewhere
Have good test coverage (in the words of Samuel Adams: Always a good decision!)
That way, when a new version of CoffeeScript is released, you have a JS backup to use in case your CoffeeScript code is broken. Breaking changes are a pain, but they're a pain common to nearly all languages except JavaScript—just ask a Rubyist who recently made the transition from 1.8 to 1.9, or a Pythonista who's still migrating their Python 2 code to Python 3.
The advice I can give for preventing your code from breaking under CoffeeScript version changes is to avoid syntactic edge cases. For example, func a:b, c used to mean func {a:b, c:c}, and now it means func {a:b}, c. That's an improvement (the old behavior was considered a bug), but some folks were caught off-guard by it. So use explicit punctuation whenever there's a hint of ambiguity; it makes for more readable code anyway.
Jeremy will have to comment on the stable/master distinction, since both branches exist but stable hasn't been updated since April (pre-1.1.0).

Check this: Has anyone used Coffeescript for a production application?

online Javascript code evaluation tools [closed]

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Closed 9 years ago.
Do you have a favorite site or homegrown page in your toolbox to help you during development of your Javascript?
Something to help you:
validate
run
debug, inspect
unit test
Looking for somewhere to paste my JS into, click a Run button, and have it evaluate the statements. This might be for simple snippets for manipulation of numbers, strings, custom objects, etc.
ANSWER (since no answers before the question was closed actually address the requirements:
turb0js - lets you step through the code without having to open the browser's console and hunt for the right JavaScript file. Also allows adding an HTML description to the code snippet, and comments from other users. DOM and Console methods don't work.
jsbin with // noprotect at the beginning of the code, to enable debugging in the browser console
Non-answers: Codepen (can't debug due to its autorun on edit creating a new script); JSFiddle (no direct support for the browser console)

Give a look to JsBin it's a great online tool for collaborative JavaScript debugging...
You can easily incorporate the most popular JavaScript libraries, and you can even use it for Ajax Request Debugging...
Check the introductory videos...

jsfiddle.net is what you need

JSLint helps a lot for validating JS.
In terms of running/debugging, I use Firebug on Firefox, and Opera/Safari/IE8's built in JS debuggers. (None of these are online, but all are pretty powerful.) I think that Firebug Lite would make for a decent online JS debugger (in that it's a bookmarklet instead of a plugin or specific browser feature).

It's a Firefox extension, not an online service, but you should look into Firebug if you need to execute arbitrary JavaScript for debugging. Or Firebug Lite if you need support for other browsers.
If you're using a WebKit based browser, (Safari or Chrome), then you can use the Web Inspector. I think that IE 8 and Opera also have equivalent features.
If you need to run JavaScript from the command line, you can use SpiderMonkey directly; it has a JavaScript REPL that you can run.

You can run/debug javascript online with Overbyte

Decent JavaScript IDE [closed]

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Closed 11 years ago.
What is a decent IDE for developing JavaScript, I'll be writing both client side stuff and writing for Rhino. Ideally It needs to run on Mac OSX, although something that runs on Windows too would be nice.
ADDITIONAL:
Having had a play with both js2 and Aptana, I think I'll be continuing to use Aptana. Mainly because I find emacs a bit hard to get my head round, although I did think that the error hi-lighting in js2 was better than that in Aptana.
I'm still looking for a way to visually debug my js code that is running atop Rhino...

Aptana IDE, absolutely. Stable, great syntax support for all the major javascript libraries, very good css and html editors. Also good support for php, air, ruby on rails and iPhone app development (I never tested this one).
Aptana can also connect to remote site via ftp (sftp in the pro edition) and to svn and cvs repositories.
It's based on Eclipse, so it's not exactly a lightweight application. But it's really, really good. You can also use it as an Eclipse plugin if you develop java wab app, but when I tested it in this version, about 1 year ago, it was not stable. Much better to use the standalone version.

If you're familiar with Emacs Steve Yegge's js2-mode could be worth a look.

Aptana Studio, both standalone and Eclipse plugin versions were quite ok last time I used them.

I have found the Spket Eclipse plugin very useful.

Take a look at WebStorm HTML/JavaScript Editor. It's lightweight and runs on MacOS. It supports debugging and running your code right from IDE and has very smart autocompletion capabilities for JavaScript both DOM-based and browser-based.

Komodo Edit/IDE is definitely the best IDE/editor (that I have used) for developing JavaScript.
Notable features include live error reporting, JavaScript macros and syntax auto-complete for ALL major frameworks!

If you have a very big application written in Javascript, there's only IntelliJ Idea. It parses multiple Javascript files and highlights not only syntax errors but undeclared variables and functions, allows to jump from function call to function definition, and more.
I've tried Emacs (because that's my favorite editor) and Komodo, and they don't come close. I guess it's the same for Eclipse.
Personally, I think that superior parsing and navigation abilties of Idea are only required when you're working with crappy undocumented code, otherwise I'd happily write the code in Emacs using js2-mode, but I'm working with huge poorly documented and buggy framework and it really helps to be able to jump to the source of the function or superclass to check how they work.

Recommendations for Javascript Editor on Windows? [closed]

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
Closed 10 years ago.
Are there any good recommendations anyone can provide for a good Javascript editor on Windows?
I currently use combinations of FireBug and TextPad but would hate to miss out on the party if there are better options out there.
Thanks.

I know jsight already mentioned this, but Aptana Studio really is a great, free editor for JavaScript if you find yourself doing a lot of work with it - it has great support for most of the well-known libraries. If it were not for the fact that I work with C# in addition to JavaScript, I would use Aptana for all of my work.

I use NotePad++ and am happy (of course, that is when I am not using Visual Studio).
NotePad++ contains support for intellisense type feature as well.

(This is a cross-answer post)
Netbeans
I've tried out all of the above and my vote goes for Netbeans, which has been mentioned. However the answer didn't really sell you on the features which you can find here.
It has:
Intellisense including jQuery built in
Extended (Eclipse-style) documentation for functions
Function and field outlining
Code folding
Refactoring
It makes Visual Studio 2010's Javascript support look very primitive.

The Zeus editor has support for Java Script.
It has the stock standard set of features like code folding and syntax highlighting features etc, but more importantly Zeus is fully scriptable and Zeus scripts can be written in Java Script.

In case you're a .Net programmer: VS 2008 has pretty great JS support including intellisense on dynamically added methods/properties and comfortable debugging.

The best that I've ever used is Netbeans, although its kind of heavyweight for some tasks due to being a fullblown multi-language IDE (not just Javascript). I've also had pretty good experiences with Aptana IDE, though, and I hear that IntelliJ is good if you don't mind paying the price.

WebStorm. If you have used any Jetbrains products you'll love it. It has Autocomplete and all the other javascript goodies. Even node.js support is provided. Check it out

If you are using eclipse, then I would recomend JSEclipse

I'm still a huge fan of HomeSite, even though Adobe discontinued development in May 2009: http://www.adobe.com/products/homesite/.

Both NetBeans and Eclipse have JavaScript editing support. The latest version of NetBeans actually does a really good job. They are both free and you can use them for other languages as well, this way you have a chance to get to know the IDE and the shortcuts as well.

Komodo Ide or Komodo Edit of course.

Editra may be worth a look, the code colouring isn't bad, and I believe it has plugins to enable script execution.. Although I have not used this myself.

GVim is still awesome - not only for JavaScript for for almost all languages.