With GWT, we can write code in Java and have it translated to JavaScript code.
With Script#, we can write code in C# and have it translated to JavaScript code.
It sounds GWT and Script# will save web developers from suffering javascript pains. Then, why these tools haven't been dominant? Why still people dedicated to write javascript code?
Multiple reasons, and which one is most important differs from developer to deverloper. Here are two:
Because JavaScript is a more nice/flexible/powerful/(insert adjective of choice here) language than Java/C#
People don't trust the output generated by GWT/Script#
I can speak for only GWT, but here's the things that I think are holding it back:
compile time (GWT takes a long time to compile, javascript changes are instant)
learning new language (a lot of web developers don't know how to code java)
FUD over leaky abstractions and compiler. People fear a compiler making javascript for them and the leaky abstractions thing. Both are just FUD in my opinion, but that's doesn't make it any less of a reason.
people often don't understand where and how to use GWT and are put off by it because they try to wedge it into the wrong holes.
There's a perception that GWT was created to allow back end developers to code javascript, but it's not the case at all.
The whole idea of using VerticalPanels, HorizontalPanels, FlowPanels and FlexTables is foreign to people who have already learned how to lay things out in HTML.
Google is bad at marketing. No offence GWT guys, but if it was marketed/showed off a bit better it would have taken off like hotcakes
Lack of great widget libraries for GWT. The widgets that come with it by default are good, but we need a bit more. Libraries like GWT-ext aren't helping in my opinion, because they are just attempts to wrap javascript libraries in GWT, and don't take advantage of the power of coding in Java.
Steep learning curve for web developers, because it's framework is more Swing like than HTML like.
I still use it in my day to day coding, but I've long accepted that it's not about to take off.
For UI development, working in JavaScript is significantly less painful that Java. Would you use a framework which translated assembler to Java to write your Java apps?
Most of the 'pain' with JavaScript was due to browser incompatibilities, which has changed due to large JavaScript libraries (eg dojo), and improvements in the browsers themselves.
Because of Leaky abstractions and because Javascript is a much more elegant and suitable language for ui than Java or C#.
because GWT ist not a one-size-fits-all solution.
GWT ist great and saves a lot of time for java developers who are writing rich internet applications.
BUT!
for my unserstanding, it is quite hard to write a GWT site Seo-friendly.
its impossible to have a non-javascript fallback.
it is not truly optimized for loading speed.
One way to look at (x)HTML, CSS, and Javascript is as the worlds most flexible UI system. Systems like GWT trade some of that flexibility for stability (note: I'm not super familiar with GWT outside the basic premise). There are a lot of software and/or service oriented shops that use the flexibility that (x)HTML, CSS and Javascript provide to differentiate themselves in the marketplace.
Imaginary conversation.
Client: I like the UI you built, but can we make this 20 pixels wider, change the hue slightly, and have an additional floating prompt when you rollover this half of it.
GWT Shop: Yeah, unfortunately the GWT framework doesn't support anything like that without major hacking and/or a lot of extra work that you don't want to pay for.
(x)HTML/CSS/Javascript Shop: Yeah, we can do that without too much trouble, here's an estimate.
I'm not arguing pro/con here and it's certainly more complicated that the imaginary conversation implies, but there are shops who, if forced to adopt a GWT like approach, would loose a competitive business advantage, so they're not going to do it.
The problem with JavaScript isn't the language itself, which is quiet good in my opinion, it is, because JS is misunderstood and people don't take it seriously and don't learn it, but copy & paste crappy scripts without understanding the code.
Secondly, InternetExplorer, JScript and the messed up DOM implementation ruined the image of the language.
But the main Problem is, you have to understand how the DOM and JavaScript works to write GWT code. It's the same as in JSF development, where you have to understand HTML and CSS. It is not like writing Java, where you don't have to understand the whole bytecode.
If your a jave programmer and dont want to learn jave script or care about how IE version deal with Js then GWT is the way to go!
Related
I've used Scala.js, and enjoyed it, for writing web page functionality.
I wrote some graphics-related functions that draw pictures on the Canvas, for instance. I'm interested in porting some of that code to Adobe Illustrator and Photoshop. They offer scripting in three languages: (1) AppleScript, (2) JavaScript, and (3) Visual Basic. Of course the API is quite different than the Canvas and will offer many specific, powerful functions that I would like to take advantage of.
My program will be rewritten and expanded considerably, so development will continue. What I wonder is whether I can continue to develop in Scala and if Scala.js can be used to write code for Adobe software, or really any software that scripts with JavaScript.
I figure that I have to create some kind of interface to the Adobe API. What would that involve? Would that code be written in Scala? Would it be a plugin to sbt? How much would I have to learn about the internals of the Scala compiler?
Is it worth doing this, or should I choose instead to develop in JavaScript? (I don't really want to write in JavaScript directly because I've had bad experiences with it in the browser, but I can't say I'm an expert in it.)
(Note that I'm not familiar with much of the Adobe API yet... I'm just investigating now.)
Should be pretty straightforward. The key is that you'll need to build facades -- strongly-typed Scala descriptions -- for the APIs you care about in Illustrator and Photoshop. This isn't particularly hard: you only have to worry about the functions you actually want to call, and you describe the function signatures in Scala. With a little practice, this becomes pretty easy -- it typically takes a minute or less per function once you have the hang of it. (I maintain the jQuery facade, which is one of the larger ones, and banged out most of it in an afternoon once I was in practice.)
Assuming that they are using reasonable standard JavaScript, that's probably most of it -- you define those facades, write Scala.js code to use them, and plug the compiled JavaScript into the tools...
How does GWT compare (or can it be compared) to Javascript frameworks such as backbone.js, angularJS, Ember, JQuery, etc.? Do they aim to accomplish the same job, making them competitors, or can they be used together?
Yes and no. While GWT's compiler is essentially a Java-to-Javascript converter, the benefits it offers far outweigh anything I've seen from any popular JS libraries.
Since GWT-based apps are written in Java, they gain many of the benefits thereof, such as being strongly typed and extremely easy to refactor. If something changes that affects another class, you know it immediately. And for those things that Java isn't great at, you can always use Javascript to handle the case with JSNI. Google has also provided a great plugin for Eclipse which allows you to debug your code like nothing I've ever seen of a JS library. Another benefit of this is that you write your client- and server-side code in the same language, and GWT does the heavy lifting of tying them together.
There are also the benefits of the automatic generation of multiple permutations. GWT kicks out a copy of your code that looks and behaves identically (inasmuch as is possible) on the most commonly used browsers. Your clients all see the same thing without you carrying the extra weight. You aren't responsible for writing endless lines of code to deal with those countless browser idiosyncrasies that have plagued web developers forever. While to some extent these things are handled by some JS libraries, GWT makes it completely effortless.
In my experience, the libraries you mentioned are all great in their own right, but simply can't provide the powerful debugging, portability, extensibility, maintainability and portability that GWT does right out of the box. GWT isn't really built to work with other libraries, and instead gives you the capacity to do (mostly) everything those libraries can without their help. (Of course that isn't to say that you can't use other libraries wherever you want...you can if you really feel the need to do so.)
So in my opinion, no, there is no competition. GWT is the figurative heavyweight champion in this arena.
I am new to computer programming and have some experience programming with python. I am thinking of developing a program that does physics simulations (projectiles, circular motion, damped simple harmonic motion systems etc.) as a hobby project. I would like to write the program that it could be run by a non-technical user(my fellow students) on a variety of platforms (mac, windows etc.) without any setup and python doesn’t seem to be a good option for building such a program so I am looking for an alternative. JavaScript has caught my attention, as it seems to be quite powerful on modern browsers, especially in conjunction with HTML5. I would like to know whether it is suitable to use JavaScript for this type application, and some information as to where I should start (I have no JavaScript knowledge)
Thanks in advance!
Yes I did have a look at the similar threads on the site but I want write something by myself than using a 3rd party library (other than for the frontend, if possible) :)
What is actually your question? :)
Can you write a physics simulation in Python?
Yes, of course.
Can you write a physics simulation in Javascript?
Yup.
Will it be useful?
Yes, probably.
Will it be efficient?
Not as efficient as an implementation with C, to be sure. But for small-scale simulations should you should have quite enough power with current JIT javascript interpreters. Tens or hundreds of objects on 30fps looks like a safe approximation, I think.
Can you make use of modern HTML when writing a physics simulation in JS?
The simulation and the display are two different things, but yes, if you want to make a graphics frontend to your simulation, the modern features of HTML and CSS could be certainly useful. But if you write it in any other language, you still have nice choices for visualization.
How to learn JavaScript?
There's plenty of tutorials online, but I don't know any particular one to recommend; perhaps anyone else can fill for me here.
As mentioned by Kos languages that are as High Level as Python or Javascript might constrain you. But later on you can still move critical parts to C-Code. (-> Regular shared Library or even Browser-Plugin)
For JavaScript I recommend you the Mozilla tutorials: https://developer.mozilla.org/en/javascript
Check out the "JavaScript Guide" in particular and keep in mind that not every Browser supports JavaScript 1.7. By the way, you should also checkout jQuery. Actually it might be easier to start right off with jQuery because you need some highlevel library anyways.
By the way: You might also want to check out Processing. (www.processing.org) It might be perfect for you as you are new to programming and it has a lot of awesome vizualization features. It basically a simplified Java with a very easy to use library. You can checkout the pre-installed examples and start playing around. Be sure to check the Reference on the website / the forum if you are stuck with problems. Processing runs on the JVM and is therefore cross plattform.
I recommend Processing very much because you can directly see results and in any case it might be interesting for Prototyping even if you think of using another language in the future to suit your needs.
Actually there is even a JavaScript version of Processing though I never used it...
EDIT: If you plan to choose JavaScript, you should use Firefox in combination with Firebug. It makes life easier when debugging...
I come from the Microsoft world (and I come in peace). I want to rapidly prototype a web app and if it works out, take it live - and I don't want to use ASP.Net.
I am not sure which web application toolkit to use though. Should I use GWT, DOJO...other recommendations? I am open to any server-side language but am looking at RoR, Php or even Java (J2EE to be precise). I am not much of a Javascript/CSS guy so a toolkit that might make it relatively easy on me on those fronts would be preferable.
Also, I am a mac user at home. What IDEs go along with the framework you would recommend?
Any recommendations guys?
If you're open to doing Java, GWT is the way to go. It allows you to have a relatively uniform codebase across client-server, and to only use one language on both.
There are some limitations to doing very off-the-beaten-path AJAXy things (which GWT makes difficult, but not impossible), but it doesn't sound like that's your use case anyway.
GWT will allow you to scale up by using more of its features as your app gets more complex - and your prototype won't be throwaway code.
If you want to write the front and back end in JAVA, and want to do complex ajax type thing, then GWT is a great way to go.
The easiest way to think about it is that building a GWT app is kind of like building a JAVA swing application that hooks into a server. Just like a swing app that uses a server you can make it fat or thin. When you're done it all compiles down into HTML and javascript, and has very good modern browser support (ie6+ ff, opera, safari).
It does abstract all the javascript and HTML away, but if you want it to look good you'll still need to understand CSS.
I think anyone who says that that it ruins MVC or that it's a muddying of client vs server doesn't understand GWT. GWT is a CLIENT side framework. And it is only used on the CLIENT. GWT does provide an RPC mechanism to hook it into JAVA (and other) back ends, but that's just a communication protocol, it doesn't mean that your server code magically becomes your client code. Sure you can write a whole bunch of business rules into your UI if you really wanted to, but you can do this with any framework, so it would be silly to say that GWT is somehow different in that respect.
GWT is a good choice, while if you choose more powerful JavaScript framework based on GWT (e.g. SmartGWT), the compiled stuff is too heavyweight.
Choose direct JavaScript if you need a compact project.
I am a fan of GWT, however I am very familiar with Java. I found it to be intuitive, and surprisingly easy to get good results quickly. If you are to use GWT, then you'll definitely want to use the free, and immensely powerful Eclipse IDE.
One disadvantage of GWT is that it requires Javascript to be supported by the browser, there is no "graceful degradation".
We have evaluate a large list of frameworks and have decide us for Echo2.
You need only to code in Java. Javascript you need only if you want write your own components.
There are no startup performance problems with large projects like GWT.
You can use the full range of Java in your client code because it run on the server. In GWT you can use only very small set of Java classes.
The IDE for Java is Eclipse. This is independent of the used framework.
I'm a fan of jQuery, the chainability of actions, traversals, and commands is really powerful. A good friend of mine is crazy about Mootools, he works at a Java shop FWIW. He mentioned a cool feature of Mootools is that you can specify the functionality you want the framework to include and it will generate the entire library on a single line in a file that you can include on your page to minimize the weight of the framework (pretty cool feature). Really it just depends on what you are most comfortable with. jQuery has great tutorials, is super fast, and can be used along with other javascript frameworks.
Not related to GWT, but have you considered other backends that GWT could work nicely with?
Grails is one backend that ties quite nicely with GWT.
Personally, I would avoid server-side frameworks that try to embed or hide the client-side framework. I'm sure that GWT is great for getting something going quickly, and is probably fine for certain kinds of applications, but you'll probably run into lots of problems "on the edges" for more complex applications. Decoupling the client framework from the server-side framework avoids those problems.
I am a .NET webdev using ASP.NET, C# etc... I "learned" javascript in college 5+ years ago and can do basic jobs with it. But I wonder if it is useful to become proficient in it.
Why should I learn Javascript?
Is it more advantageous then learning JQuery or a different library?
Yes, definitely learn Javascript before you learn one of the libraries about. It's the whole walk-before-you-can-run thing.
Make sure you add these sites to your bookmarks:
Mozilla's developer site: This contains the reference to the Javascript API in Mozilla. This will help you make sure you're writing code that Firefox understands.
IE's site in Microsoft Developer Network: The same, for IE.
W3's reference of DOM for HTML: In most web applications today, the Javascript code manipulates the DOM, which is an internal keeping track of the objects displayed on screen (but you already knew that, right ?) This is the reference to the DOM API. It is language neutral, which means it does not target Javascript, but these methods exist in Javascript too.
Douglas Crockford' site: Doug Crockford is THE MAN when it comes down to Javascript. The articles in his page are a must read. Because Javascript has closures and first-class functions, he believes it is closer to Lisp and Scheme than to other languages. And he teaches you how to greatly improve your code with these language features.
Yahoo Developer network: You may also want to check this. I'm not a regular visitor to this site, though, so I can't really say much about it.
Yes, absolutely you should learn JavaScript if you are doing web development. I highly recommend JavaScript: The Good Parts, by Doug Crockford. And, JQuery is a great framework to use (this site uses it) -- it kind of depends on what you are trying to do -- YUI and ExtJS are also very nice.
The answer is simple.
Hands down yes. There's a reason that Google have made such a big fuss about the V8 JS engine for Chrome, why Mozilla are working on TraceMonkey for Firefox and why Webkit have been working on Squirrelfish for a while (now Squirrelfish extreme). It's because JS is becoming more popular by the day.
Javascript is one of those languages that spending a few hours learning will probably teach you 99% of what you will ever really use. I would imagine you are at the point in your learning of javascript that you know more than enough now and just learn one or more of the frameworks now.
I would recommend brushing up on your non-frameworked javascript first. Refreshing/learning basic concepts of dom manipulation and what not. Like learning how to build a linked list, stack or queue in C++ before learning how to use the STL (standard template libraries).
In addition to brushing up on straight javascript, it might be good to get into a framework that doesn't abstract and change the way things work so much, for instance Prototype. You code with it very much the same way you code with straight javascript. Read through the Prototype code, learn how to make classes, and do some fancy stuff. From experience, I can say reading through the Prototype.js helped me learn alot.
After messing around a bit, then I'd say go for jQuery. If jQuery didn't, literally, change the way you write code I'd say go for it first, but learning how to build classes and js inheritance and what not can be a very important lesson for someone who wants to become fluent in JS.
Learning javascript is recommended for any web application developer. Why?
You will better understand the possibilities, limitations and dangers related to developing a web application
It is a boost for your career, if you are working on a web application that has a user interface.
However, learning javascript is usually a trade-off between a programming language and another. You should consider whether javascript is relevant for your career or project.
Unless you want to really get into javascript, I think you'd be better off learning enough JS to leverage one of the tried and tested javascript libraries out there.
One thing nice about JavaScript is that it is quite different from mainstream languages such as C#, VB.NET or Java. Learning it, especially if you have occasions to use it, will give you another insight on programming, and that's always good. I think it's worth learning it.
If you are doing web development then at some point you are going to get exposed to Javascript or ECMAScript at some point in your career for any one of a number of reasons. At a minimum you should know enough Javascript to be able to be able to validate user input; however, the web is moving in the direction of using more an more Ajax so you should also know enough Javascript to properly leverage one of the major libraries out there such as jQuery.
As some of the other users have noted, you can learn most of what you need of Javascript on a day to day basis in a single day or a couple of afternoons. If you want to get more advanced with Javascript then you are going to have to invest much more time in learning the language but odds are that unless you seek out this type of work that you are not going to encounter something that a preexisting library doesn't already exist for.
If all you want is to do some simple UI-effects and the like, I suggest you just pick a library and go for it!
Using libraries eliminates all the flawed implementations of JavaScript and provides you with an API which is the same across all browsers. And if you're working together with others it is also a great way of implementing code-standards and best practices.
Learning a second programming language is always good.
By the sound of it, JavaScript is a language that you use, to it will be of practical use too. As a web dev, it has been recommended to me in a review that i learn at least basic JavaScript.
A library such as jQuery is essential for web development thse days, so you could learn that too.
I don't think a lot of deliberate learning makes sense (but of course you need some basic knowledge), but I also think after some years of web development you'll become pretty proficient in the language anyway :)
If you are a webdev then yes, you should be proficient with Javascript. Javascript is a major part of making web apps as interactive as desktop apps.
With that being said, learn to use one of the cross-browser compatible libraries like JQuery, Prototype, etc. We do not need to have any more single browser crud created using Javascript, just because any real man/woman rolls their own.
A few things to learn in Javascript:
1. Basic syntax
2. The various flavours of function declaration.
3. Passing functions around and how to use passed in functions.
I recommend Jeremy Keith's books: DOM Scripting and Bulletproof Ajax. After you become more fluent in JS I would recommend a JS library(I use jQuery, but that is not important).
JS is important to learn. You cannot use a framework without the proper understanding of how it works. That is doing things backwards.
i thing you should have a good knoloedge base of language specification and DOM (Document Object Model). it means,you shoud know how find/create "page object" an edit properties. Also you should have an idea of "object oriented" javascript tecniques, which the starting point of a lot of framework. you don't need learn specific framework if you don't use it. simple keep in mind generic base concept!
I'll go with the opposite answer most are putting out there. Learning javascript as a developer these days is almost pointless. The language is similar enough to java/C# that it's syntax and semantics shouldn't be lost on you.
What you should learn is jQuery.
As you use jQuery you'll pick up the most common things you'll ever need from javascript anyway.
If you're involved with the Web in anyway then the answer is "Yes, always". Maybe an embedded or system's programmer could get by without JavaScript, but not a webdev.
Most of the libraries are designed to alleviate some of the pain of interacting with a multitude of browsers. They will not abstract away core JavaScript functionality.
Yes, you should learn JavaScript. Sooner or later you will need to use it!