More Powerful language for client-side web apps: JavaScript or C#?

Question

Concerns over Microsoft's future with Silverlight, HTML 5 and Windows 8 have led me to reconsider plans to develop a business app over the next few years in Silverlight.

It can be difficult to define what powerful means. Here I mean to ask this as power in the sense that Paul Graham describes, as what you can express with the language. I'm not sure but it seems that even the latest features of C# 4.0 such as dynamic types, anonymous functions, closures, and even LINQ exist in JavaScript. Do you think there are plans to add additional power to the JavaScript language in its next release?

Also, to deal more with the HTML5/JavaScript stack vs. the Silverlight/C# stack: which is or will be more powerful in the sense of what capabilities it gives to developers and their applications? e.g. WCF communication, tools, UI controls...

Answer 1

Silverlight and C# IMO are far more productive than HTML 5 / JS. This is true right now without a doubt, but I expect it to be the case for the forseeable future. To achieve the same amount of UX quality, it takes far less time with SL than with HTML 5 / JS.

Almost by definition, plug-ins like Flash and Silverlight will be able to evolve faster than standards such as HTML 5 / CSS 3 / ECMAScript, etc. This means that they will stay ahead of the curve from a development productivity and user experience perspective. In addition, you won't have to deal with browser compatibility issues which are big headache right now with HTML 5. However, as a trade-off, you have to deal with getting your users to install the plug-in, and you will reach less people because of that. Also, the amount of devices and browsers you can support are limited. If you have a captive audience this might not be an issue.

I have a blog post that goes into details about some of this stuff if you are interested:
http://rationalgeek.com/blog/post/Silverlight-vs-HTML-5.aspx

Answer 2

C# is a server-side language, while javascript is built for client-side,

C# can't really become a challenge for js, until a C# parser comes in the market.

Answer 3

Honestly, Silverlight would be my choice.

If you have any concern that Silverlight (read Microsoft) will let itself not be robust enough, powerful enough, or expressive enough to compete with the likes of JavsScript, I think those concerns are unfounded: The Future of Microsoft Silverlight.

Other interesting bits Common sense on Windows 8, Silverlight, ... :

"The Windows team is not just delivering native code APIs, but also an HTML and JavaScript API. This is a break with the past, hence the talk of a new platform.

When it comes to desktop applications, would not Silverlight or something .NET based be a better choice than HTML5? I can see both sides of this. On one side is all the effort Microsoft has invested in .NET and Silverlight over the past decade. As I’ve noted before, I see Silverlight as what client-side .NET should have been from the beginning, lightweight, secure, simple installation, but with support for C# and much of the .NET Framework which developers know so well.

On the other hand, I can see Microsoft wanting to tap into the wave of HTML5 development and to make it easy for web developers to build apps for Windows 8.

In the end, developers will most likely have the choice. That puts pressure on Microsoft’s developer division to provide strong tools for two different development models; but I think that is what we will get."

I don't think there will be any issues with Silverlight 'catching up' ... JavaScript is still an option you can't go wrong with. I just don't see Silverlight being slow to progress.

Answer 4

According to RIAStats the penetration level for Silverlight and browsers with some form of html5-type support (either natively or with a shim of some sort) is about the same at 75%. They both lag a bit behind flash, which is somewhere around 97%.

If my choice was between a C#/Silverlight application and a JS/html5/css3/* application, I would choose the silverlight route, but that is because I know C# and the Xaml/Silverlight way of doing things far better. The tooling support, especially with VS2010 and Blend4, is FAR superior than what you can get with the Javascript app route, but if you're a javascript "ninja" then the equation changes.

As of right now, Silverlight can do things that are either impossible or ungainly with javascript in the browser, and I don't see that gap narrowing any time soon.

It seems to me that people, when arguing that html5/js is the "future of the web", people tend to forget that while that is true as far as we can tell now, there are still many instances where what you want is not a web application, but a line of business type application that just happens to run on the web. In those cases, Silverlight will continue to be ahead of html5/javascript for quite some time.