JavaScript vs Silverlight: An answer

An article was published at (titled “JavaScript vs Silverlight”) arguing that JavaScript is better than Silverlight. Unfortunately, there is no way to post comments on that page (weird, really) so I decided I would post my answer here.

Read the rest of this entry »

Print | posted on Wednesday, July 14, 2010 2:49 AM


# re: JavaScript vs Silverlight: An answer

left by Jason Cook at 7/14/2010 3:37 AM Gravatar
All "product A vs product B" blog posts fall into one of three categories:

1. I love product A, am uninformed about product B, but will bash it anyway because I hate and fear the unknown.

2. I love product A and want to learn more about product B because I actually might switch.

3. I use both product A and product B regularly, am informed about both, and can write an intelligent discourse comparing and contrasting the two.

Jupiter is a Javascript consulting shop that specializes (perhaps exclusively) in JQuery. Since more than 90% of the posts on both their blog and their Twitter are about JQuery, I suspect their readership is interested in the same. So the real question is, which of the above do you think motivated the post?

# re: JavaScript vs Silverlight: An answer

left by Dave Campbell at 7/14/2010 3:44 AM Gravatar
I sent them an email and thanked them for posting without full knowledge of their subject and not providing a way for feedback from people that would know their subject.

Your post is great, Laurent... good info, give and take, but at least speaks the truth.


# re: JavaScript vs Silverlight: An answer

left by Dave Swersky at 7/14/2010 4:00 AM Gravatar
It's good to see a well-considered argument against ill-informed BS. If you're going to compare two technologies, you should at least be familiar with both. Justin's assertion that you can only use WCF with Silverlight clearly demonstrates his total lack of knowledge on the subject. Bravo, Laurent, for clarifying the issue!

# re: JavaScript vs Silverlight: An answer

left by Corrado Cavalli at 7/14/2010 4:05 AM Gravatar
Great post Laurent, can't write it better...

# re: JavaScript vs Silverlight: An answer

left by Justin Meyer at 7/14/2010 4:21 AM Gravatar
I just linked to your article and tried to clarify at least one of my points that was easily misunderstood (WCF and Silverlight).

I'm happy to keep discussing.

# re: JavaScript vs Silverlight: An answer

left by Rodrigo Díaz Concha at 7/14/2010 4:21 AM Gravatar
I just totally agree, well done Laurent!

# re: JavaScript vs Silverlight: An answer

left by Justin Meyer at 7/14/2010 4:36 AM Gravatar
The only thing that motivated my post was a company deciding to go with JS or Silverlight. My silverlight experience is nothing compared to my JS experience. I am extremely biased, but I pick the technology that works best. I dropped XML a few days after I saw JSON. I dropped Prototype for jQuery (and converted all of JavaScriptMVC).

I try very hard to pick the best technology for the application at hand. For this company, I tried to outline a few of the reasons why JS isn't a right fit. This was the first article I wrote for the site (the others were imported from No one was reading it. I should have been more careful.

If tomorrow silverlight provided a better, long term, approach to building applications, we'd change our domain to

# re: JavaScript vs Silverlight: An answer

left by Michael Washington at 7/14/2010 4:37 AM Gravatar
Very well written. This is now a useful blog post for people to point to when there is a "discussion".

The community thanks you for taking the considerable time to write this.

# re: JavaScript vs Silverlight: An answer

left by mentas at 7/14/2010 4:56 AM Gravatar

Comparing a simple script (JS) with the powerful programming language (C#)...

What about XAML? Debugging? LINQ? Libraries & Frameworks? Object-oriented programming? Reflection? about 10x development faster? MVVM model? WOW

It's ridiculous!!!

Note: HTML/CSS/JS its not about application... its about content (document)... never can be compared with SL/Flash (true RIA/UX frameworks), especially with SL

# re: JavaScript vs Silverlight: An answer

left by Paulo Aboim Pinto at 7/14/2010 5:07 AM Gravatar

I agree with all you write and two more things.

1º Debug with Visual Studio make our work much easier that using print to the screen.
After learning how to use debug in VS I just don't want anything else.

2º I use the same language in all components in Silverlight... ok! I use too XAML, that it's not a language but a representation of the screen.
Using JavaScript I have to learn JavaScript (with hardcore debugger), HTML (that's not hard), Java to create my WebServices to create Business Layer and Data Access Layer.
We have to be master in 3 languages.

With Silverlight we only have to know: C#

I'm sure that this guy does not know anything about fast development using just JavaScript.

By the way I just HATE JAVASCRIPT.

Paulo Aboim Pinto
Odivelas - Portugal

# re: JavaScript vs Silverlight: An answer

left by Justin at 7/14/2010 5:23 AM Gravatar
I hope you mean't to say is all I know about is fast development using JavaScript. Or maybe I don't know anything about fast development BUT by just using just JavaScript.

However, you're articulating one of my points, the 'lock-in' that happens with silverlight backends. It's not a true lock in. It's just what happens. People pick WCF b/c that is the first demo they read and stick with it.

Have you used firebug? You don't print to the screen.

But, you articulated a very good point for using Silverlight, skill sets. If you are building something for a small internal app and don't know JavaScript, then Silverlight is a great choice.

But this is a big application, with millions of users. Developer apathy or ignorance isn't a good reason.

# re: JavaScript vs Silverlight: An answer

left by Matthew at 7/14/2010 5:56 AM Gravatar
Ignorance is a great reason. If I have 10 engineers and all of them are effective C# programmers and only 2 of them are effective JS programmers, I am going to go with the technology that my team is more effective with.

I like this article, it is intelligent and well written. I use JS and SilverLight and am equally effective in both. You should choose the technology that is right for your project but just as importantly, you should choose the technology that is right for your team.

# re: JavaScript vs Silverlight: An answer

left by Josh at 7/14/2010 5:58 AM Gravatar
thanks for the insightful read. if there's one thing I can't stand it's people who insist that their technology of choice is better than yours, and you're wasting your time if you're using any other framework.

poo on that mentality. there is no single tool for all jobs, only a master craftsman who knows which is the right tool for a particular job.

good stuff, thanks again!

# re: JavaScript vs Silverlight: An answer

left by Kelps at 7/14/2010 6:08 AM Gravatar
I agree with everything you said. One cannot compare 2 technologies and be fair without knowing them really well, and even then, it is almost impossible to be unbiased. It is all relative and depends on your point of view and experience.

The thing is: Choose what is right for you and your needs.

# re: JavaScript vs Silverlight: An answer

left by Jeffrey Langdon at 7/14/2010 6:21 AM Gravatar
Great post Laurent. I always find it funny how many "comparison" articles really compare two dissimilar technologies. Oh well, usually a good laugh reading them. ;)

# re: JavaScript vs Silverlight: An answer

left by rekna at 7/14/2010 7:47 AM Gravatar
I've used jQuery extensively and silverlight as well... It's scary to see the evolution of jQuery plugins, where they are using a string parameter to specify which method they want to execute on a plugin, just because they don't want to pollute the jQuery namespace.... if it were not for jQuery I would never javascript because of ridiculous browser differences. And even with firebug, debugging javascript is less convenient then debugging c#.

# It's a trap.

left by 1010011010 at 7/14/2010 8:13 AM Gravatar
I don't trust silverlight, because I don't trust Microsoft. Silverlight will eventually be windows-only. It's a trap, essentially.

# re: JavaScript vs Silverlight: An answer

left by Laurent Bugnion at 7/14/2010 9:19 AM Gravatar
@1010011010: So Microsoft will invest money to *remove* the existing compatibility layers (that they went at great length to implement) with Mac OS? Mmmh yeah I don't think so :)

@Mike: I am pretty sure that SL will come to Android eventually (though I do not have any info on that). As for Nokia, there is Silverlight for Symbian already. As for open... maybe when HTML5 is ready we can move to it. In the mean time I will stick with what I have, and what I earn my life with ;)

# re: JavaScript vs Silverlight: An answer

left by Max Paulousky at 7/14/2010 9:57 AM Gravatar
Laurent, you can use to get more or less unbiased information about Silverilght staistics

Thanks for your arguments!

# re: JavaScript vs Silverlight: An answer

left by Laurent Bugnion at 7/14/2010 10:34 AM Gravatar
@Mike: There is already a version of Silverlight for Linux (Moonlight). It is not developed by Microsoft but by Novell with some support from Microsoft. They have all interest to get the framework running on multiple platforms.

I am not asking developers to choose Silverlight. As I said, the intent of this article was to correct wrong statements made in the original. That is all that was intended. If I judge by the number of headhunters calling me to offer Silverlight development jobs, developers would be well advised to add Silverlight to their skills (in addition to JavaScript, HTML and other technologies). But then again, if they don't, that means more work for me, which is good.

Nice definition of a niche product, a technologie that runs flawlessly on all Windows PCs (in and out of browser), most Macs (in and out of browser), some Linux boxes, all Windows Phone 7 (they're coming, you know ;), etc etc. I can live with that.


# re: JavaScript vs Silverlight: An answer

left by Keith Nicholas at 7/14/2010 10:51 AM Gravatar
Basically your argument is, silverlight is a bit easier at the moment.

But no matter how you slice it, the overall case for silverlight is limited, it *will be* / *is* in direct competition with HTML5/JS.

The technical points you make are meaningless. You miss the point. JS vs Silverlight will all be about what problems you will try and solve. They don't compliment each other. (they could if you want, and technically it might work out quite nice, but really, there's no point). Silverlight will plug the holes of what html5/js can't do.... but for most people, they won't have those holes. So, the business problem you have, you'll either solve it using silverlight, or JS.

Everyone but .NETers will use Html5/js, meaning the libraries, the tools, etc will develop and mature very quickly.

for .NETers, they can go either silverlight will become a niche.

So yes, silverlight is a nicer development platform at the moment, nicer tools, but ultimately its a dead end / niche technology. The bulk of the web world will not use it. People will be solving the same problems using silverlight and Js, regardless of technical merit of either platform. JS will be the richer community with far greater choice on libraries, pre canned solutions to many problems, etc etc.

so unless silverlight can offer something *significant* that JS can't, its dooooooomed. But for the moment, it's quicker and easier (ish) to do something now. (though even in .net mvc apps, I find it quicker and easier to mix in a rich js components than silverlight)

# re: JavaScript vs Silverlight: An answer

left by Laurent at 7/14/2010 11:13 AM Gravatar
@Keith: Again, I am not trying to make another point than correcting wrong information entered in the original article. Technology is all about evolution. I used to do a LOT of JavaScript, then moved on to something else when it gave me the opportunity to finally make the apps I was dreaming about, and who knows what will happen in 5 or 10 years. Honestly? I couldn't care less as long as it allows me to create beautiful user experience and powerful applications.

Your point is interesting and have some validity if Silverlight was about the web. However, it is not. On the web, you may see it as a direct concurrent to JavaScript/HTML5. I say, we'll see when HTML5 is there. I believe that there is room for all. As for Silverlight, with version 4 we already develop more out-of-browser applications than in browser. With the Windows Phone, it will be an even more important portion. As I said, it is an evolution. Even if suddenly Silverlight stopped working in web pages, it would still have a future. As for JS.... it is cool on the web. Let's see what web applications and web browsers look like in 5 or 10 years.


# re: JavaScript vs Silverlight: An answer

left by Laurent at 7/14/2010 11:18 AM Gravatar
@Mike no as I said, I was answering to this article: and correcting some wrong statements.

As for waiting and seeing, it is of course a valid attitude. In the mean time, I am having a lot of fun developing Silverlight apps. The nice thing is that what I learn now is applicable in other platforms too, and many many principles and patterns will help me later when I move to another technology and other platforms. This is the story of a developer's life (in my case I worked in C, C++, Java, JavaScript, HTML, VB.NET, VB, VBA, C#, etc... on ASP, ASP.NET, embedded devices, Mac OS, PCs, etc etc etc. Learning is fun.


# re: JavaScript vs Silverlight: An answer

left by mhitza at 7/14/2010 11:54 AM Gravatar
I for one always find it hilarious when Javascript is compared to Flash/Silverlight.

While I love Javascript, I for one find it extremely hasty the way everyone is pushing it as a replacement towards Flash/Silverlight.

All these technologies have a common applicable ground, but will still be relevant independently in the foreseeing future; as I agree on the 'at least 5 years' of html5 and Javascript new API adoption by all the browser vendors, there are still large numbers of IE6 users.

P.S. server side javascript was clearly expectable given the high adoption of Javascript lately (especially thanks to jQuery), and I do see NodeJS as something promising.

P.S.2. a bigger text box in the comment form wouldn't hurt :)

# re: JavaScript vs Silverlight: An answer

left by mhitza at 7/14/2010 11:57 AM Gravatar
And another thing that I forgot to ask. What exactly do you feel it's missing from Firebugs debugger? It worked wonderfully for me when I had to debug Javascript code.

# re: JavaScript vs Silverlight: An answer

left by Michael at 7/14/2010 1:33 PM Gravatar
@Laurent, Microsoft doesn't have to remove support, all at once, one day. They probably won't do that. They just have to start adding features that are windows-only, and let the other platforms rot. Over time, it will be a windows-only thing. Chances are much higher that they will do that (again).

# re: JavaScript vs Silverlight: An answer

left by Joe at 7/14/2010 3:37 PM Gravatar
What concerns me is about the 2-5 year vision. What happens to all that Silverlight code when IE9 has been Windows updated on all PCs and rolled out as part of Windows 8? Are we really going to be left with JavaScript/HTMLDOM as the client platform for all applications? We need a bridging technology - somebody to think about the future of the browser for the long term.

# re: JavaScript vs Silverlight: An answer

left by samcov at 7/14/2010 7:15 PM Gravatar
HTML5/JS will win on the open internet, there's just no two ways about it, it's just a question of time.

Silverlight can only win if it presses it's advantages, which are the development environment, and C#.

If these things don't produce something that can't be done in HTML5, through the use of threading and multiprocessing, it will be niched and usefull, but not widespread.

However, if the model for Windows phone works, HTML is TOAST, because that model is the one that beat the crap out of IBM and the MAC.

I love Silverlight, but reality is reality.

# re: JavaScript vs Silverlight: An answer

left by Laurent at 7/14/2010 7:20 PM Gravatar
@Michael: I share the concern. Thankfully, this is an area (windows-only features) where the Silverlight community, and especially the insiders (a group of non-MSFT people under NDA, who get very early access to builds in order to test them and give feedback (I am a member)) is very vocal. Right now, the only two features that are windows-only are COM communication (because Apple does not have something similar - though MSFT is studying alternatives) and multitouch (because it heavily depends on the hardware for one, and on the OS relaying the touch information to the SL framework - an area where Windows 7 is very advanced).

Even for these two features, we talked for days (literally) on the mailing lists and debated if it was good or bad. My opinion is that, if a feature is Windows only, it should not make the cut. I would accept an exception for COM because it cannot be used on the web anyway (this is only available out of the browser with elevated permissions). As for multitouch, I really hope that Apple ups their game there to enable compatible multitouch applications.

My point is that Microsoft is under intense pressure to keep things compatible. From what I heard from the team, they are very committed to this vision on the long term. While I understand the need to be cautious about this, as an insider I can say that what I see comforts me that it will remain so at least for the foreseeable future.


# re: JavaScript vs Silverlight: An answer

left by Laurent at 7/14/2010 7:32 PM Gravatar
@mhitza: Thanks for the comment about the input box. On Chrome you can resize it ;) but you are right, I will change the CSS to make it larger.

@Joe: The 2-5 years vision is my own solely. I know that MSFT is having longer term vision for Silverlight and considering how they push it now (some say to the disadvantage of WPF), it is pretty clear what the vision is.
For me personally I don't try to read tea leaves anymore (15 years in the software industry taught me that this is futile for a single person to do so ;) so I keep my "predictions" to the 2-5 years time range ;)

That said I am not sure what you mean with Silverlight code being obsolete when IE9 is rolled out. The advantage of SL as a plugin (while it has disadvantages too) is that it works the same on every supported platform, and it will work on IE9 just as well. Did I miss something?

@samcov: I wish I shared your optimism about a single platform "winning". Unfortunately I am old enough to remember when XHTML was promised as the panacea, and we all know what happened. The truth of the matter is, the core driving HTML5 is mostly big firms (Apple, Google, MSFT etc). I cannot trust them to come to an agreement. As much as I love open source and open standards, I am concerned that each browser maker will end up pushing their own flavor of HTML5 with specific features. I really don't want to start coding with if(IE)...else if(Safari)... again. This is one main reason that drove me away from traditional web apps in the first place.

# re: JavaScript vs Silverlight: An answer

left by lixin at 7/15/2010 12:30 AM Gravatar
If Javascript builders can get Javascript something similar to MVVM, I would try to develop my applications, which are mission critical applications, in Javascript.

Really hated to write so many lines of code only for a simple function in Javascript.

# re: JavaScript vs Silverlight: An answer

left by Josh at 7/15/2010 1:01 AM Gravatar
I see Silverlight as a niche product to develop apps for microsoft framework. I don't see any point in waiting for another 2 - 5 years to see how Silverlight is doing. MS has already proved that their products do not run on anything other than windows (see Office applications, .Net framework etc). Another point to make here is SEO. Silverlight (and Flash) are not SEO friendly.

Having said that, I see Silverlight being used in internal apps. It is a great technology, but I don't see it beating HTML/Javascript in the foreseeable future.

# re: JavaScript vs Silverlight: An answer

left by Laurent Bugnion at 7/15/2010 1:17 AM Gravatar
@Josh: Silverlight runs on other platforms than Windows. Not just in the browser either, but out of the browser too, so you can even develop desktop applications for Mac OS using .NET. Moonlight is also doing very well on Linux platforms.

Silverlight is SEO friendly. Using simple techniques, it is possible to deliver SEO content for an SL application. This is honestly not a valid point to make here.

Finally, let me reiterate: Silverlight will not beat HTML/JS, nor should it even try. On the web, Silverlight is there to enhance web applications, not replace them. Plus, the focus is shifting to richer applications running out of the browser anyway.


# re: JavaScript vs Silverlight: An answer

left by moxi at 7/15/2010 8:33 AM Gravatar
"Development time: Visual Studio is the best development environment available, ..."
Really?, Are you kidding? hahahahaha LOL, obviously this is a lie, or this talks about your little experience with the world outside Microsoft technlogies, there are other projects Javascript for mobile, Flex is like Silverlight++, what about JavaFX?
You look like a newbie, open your mind, and your vision, nice post, but its so closed, Silverligth is great i like it, but there is a world outhere,
I Like your post!!!

# re: JavaScript vs Silverlight: An answer

left by Sparkie at 7/15/2010 9:59 AM Gravatar
For "In the box", I wonder if he as used Gestalt (, where you can literally use ruby or python in a webpage the same way you'd use Javascript.

# re: JavaScript vs Silverlight: An answer

left by Laurent Bugnion at 7/15/2010 10:31 AM Gravatar
@moxi, you are entitled to your opinion as I am to mine. Contrarily to what you think, in my 15+ years of software development I have touched multiple technologies (in and out of the MSFT stack) and multiple development environments. I stand by what I said, but I respect your opinion. I expect you to do the same.

@Sparkie, yes Gestalt is a very interesting experiement. When I was coding Java, I would sometimes use "invisible applets" (i.e applets that were 1x1 pixels with a transparent background) and would use JavaScript to control them. The applets could perform tasks that JavaScript was not allowed or able to do. Gestalt very much reminds me of that. I like the concept very much. For example, given that Silverlight is very efficient when it comes to network communications (be it with SOAP or REST based web services), why not use Silverlight to communicate with the services and parse the answers, and then pass the results to JavaScript.

Anyway, this underlines my point, which is that putting JavaScript and Silverlight in concurrence is futile. I see them as complementary technologies.

# re: JavaScript vs Silverlight: An answer

left by Braulio at 7/15/2010 8:53 PM Gravatar
Hey Laurent, great post.

I think the main point is... before discarding a technology really learn it and play with it, most the SL fellows come from a web background, so we have some good knowledge on both technologies.

Agree with you, ... one of the best things of SL is that you endup with something well architected that can be unit tested, not spaghetti javascript (please don't get angry with that expression, if you have worked with an average development team and tried to make something really reach you know what's that).

Altough, I have to say the main weak point of SL now is the lack of full multiplatform (SL 4.0 Linux support, iPhone, iPad, Android, ...), hope that Ms chaps will add more platforms to the box soon.

# re: JavaScript vs Silverlight: An answer

left by anirudha at 7/17/2010 7:23 PM Gravatar
your sidebarleft is very smart. how you can hide ads and fits your logo. on my blogs how i can do this.

# re: JavaScript vs Silverlight: An answer

left by Pradip Bobhate at 7/20/2010 1:33 AM Gravatar
Very good artical.

# re: JavaScript vs Silverlight: An answer

left by Erno at 8/22/2010 6:48 PM Gravatar
Another good article, also when I read the original orticle on JupiterJS one thing that bothered me was the assumption that you couldn't use Selenium to test it, something which I could've sworn I had read somewhere was possible(though not easy). So I was pleasantly surprised when I came across this in my feed reader this morning:

# re: JavaScript vs Silverlight: An answer

left by Chad at 9/12/2010 9:54 PM Gravatar
I agree with some of the previous posters. I really don't see much of an overlap between the two. Leave the websites to JS and the more advanced apps / complex UI to SL.

HTML5/JS, even when it has widespread adoption in another 5 years or so, cannot do what SL can do right now, let alone what it will be able to do then (when at version 9?).

That's nothing against HTML5/JS, it's definitely going to be powering the web for the foreseeable future, but there is a very big spot for these rich technologies to give a better experience for both the end user and the developer.

I see them both moving forward, not one replacing the other!

# re: JavaScript vs Silverlight: An answer

left by The Dev at 3/10/2011 3:56 PM Gravatar
The debate is such a joke it's funny. I am someone who has been devloping enterprise level database applications for 10 years and like others have experience in multiple platforms like .net and java.hands down visual studio provides the most intuitive Dev experience out there. Yes html5 and ms should be companions not competitors but try doing a serious data intensive app in html5 and js.vs gives an object oriented language, great controls and great patterns are availiable and js u can just used to make your apps pretty

# re: JavaScript vs Silverlight: An answer

left by Justin Meyer at 7/14/2011 5:39 PM Gravatar
Not to poke the fire too much, but now that Microsoft has seemingly all but abandoned Silverlight, have any people changed their mind?

# re: JavaScript vs Silverlight: An answer

left by Laurent Bugnion at 7/14/2011 11:39 PM Gravatar

Only people who don't know what's going on reported that Microsoft "abandoned" Silverlight. The first wave was countered by the Silverlight Firestarter event which introduced Silverlight 5 pre beta. Other waves followed. Unfortunately it seems that some people are just happy to spread wrong news and negative information about technologies which they don't master, instead of learning these.

In the meantime, we saw:
- More information about Silverlight 5, and it is on due course for release. It includes a lot of new features such as XNA-like 3D, tons of improvements for line of business development (making it more than ever the platform of choice for all business related applications) and much, much more.
- Silverlight 4 being made available on the Windows Phone 7 "Mango", the next large update available to developers already, and to the public by the Holiday season. This includes about 1500 new APIs.
- Silverlight being rumored on additional platforms. I cannot comment about these rumors as of now.
- Silverlight being announced as "running on Windows 8" by Sinofsky.
- A new "crop" of Silverlight MVPs awarded just a few days ago.

In addition to all that, many informed people commented on XAML and C# being a development platform of choice for the new "immersive apps" in Windows 8, next to HTML5/JS (and possibly C++ too), so not only is Silverlight alive and kicking, but in addition it is shaping the future of Windows development.

The future is very bright for Silverlight developers (and even brighter if you are proficient in XAML :)


# re: JavaScript vs Silverlight: An answer

left by Steve M at 3/3/2012 12:03 AM Gravatar
Nice summary article. Some more in this one

# re: JavaScript vs Silverlight: An answer

left by Bruce Le at 11/6/2012 4:59 PM Gravatar
Fast forward to the end on 2012, and it seems Silverlight will not see any future release. XAML will live on through Windows Phone 7 and Windows 8. It is still not completely clear what will happen of Silverlight, but one thing that seems obvious, is that it will probably only live on Microsofts products.
Comments have been closed on this topic.