HTML5 and the Death of Silverlight and Flash

Will HTML5 kill Silverlight and Flash? I have lost count of the number of people that have asked me that very question.

I must say that I’m concerned with these conversations. They not only cloud the individual applications of the technologies being compared, but often ignore technologies that could also be in the discussion – like Cocoa, LINUX, etc.

In addition, I tend to be more interested in looking at the future of HTML5 right now and what it means on a broader scale – without necessarily pointing to other technological tombstones.

Having said all that…will HTML5 kill Flash and Silverlight? Good question. Here are my thoughts, and I’m interested in your feedback as well.

Proper Perspectives

First and foremost, we need to address perspectives. From what lens are you looking at HTML5? If your market consists of clients that support HTML5, you should be aware that your market is actually narrower than those aggregate clients that support Silverlight or Flash.

See, our reality for current new technology implementations – as well as our future reality – is not an inherent jump from one technology stack to another. Typically someone must use these new technologies to start a trend. This serves to prove or disprove their worth, and allows the rest of us to identify their successes and failures.

The early adapters of new technologies are then rewarded by entering niche markets ahead of their competition. Unfortunately, sometimes these efforts are expended on technology that never comes to pass, or becomes eclipsed before it has a chance to mature.

All that to say,“HTML5 is ready, but not finished.”


This is not to say that it’s not finished so you better not use it. Not at all. HTML5 isn’t a 1.0v software package with bugs – it’s a fully ready implementation that will continue to grow, evolve and become more powerful.

It is new. It is exciting. It is beautiful. It’s just not finished maturing.

Browser Support

Now I have heard people say that Internet Explorer doesn’t support HTML5. I’ve also read that Microsoft claims to fully support it with IE9.

Neither of these statements are completely true – or completely false.

The conversation needs to be about to what degree each browser supports HTML5. Because it is so inconsistent, any implementation of HTML5 could cause some rather different results cross-browser.

According to the implementation scores obtained from

  • The browser with the highest user adoption trend (Google Chrome) has the highest HTML5 implementation score –
  • The browser with the lowest user adoption rate (Opera) has the second highest score.

As for how well IE9 supports HTML5? Well, IE9 scored the lowest of all the browsers, and it’s not looking much better in the beta for IE10 from what I understand.

(Now I have read comments on various blogs accusing Microsoft of trying to stall HTML5 adoption to buy time to make a light version of Silverlight. I highly doubt that’s the case, but even if it were true – who cares?)

Other sites (click here and here) offer conflicting data regarding browser usage. That said, while the data and collection methods differ, all the studies demonstrate that end users are moving away from IE in a big way and Google Chrome is picking up market share rapidly.

So what does this mean?

Not a whole lot in the long run, truth be told…especially when we consider the exponential growth of mobile browsers.

This is the conversation we should be having -- not which web browser is more popular, or HTML5 friendly. Hand held devices have completely different requirements. Whatever technology we choose, it needs to work effectively with both mobile and web-based browsers.

Bottom Line

We are in need of something new to meet the future needs of developers and end users. Highly functional interactive experiences are becoming a necessity, simply to match our competitor’s ability to wow customers and lure them in with our mobile and web-based user interfaces.

For myself – supporting as many clients as possible is the primary goal. And for the moment, HTML4 + CSS + JS is a very most broad-reaching technology set that works with most of what I have to do.

That combination is hardly a current antagonist for the likes of Silverlight and Flash.

Answers to FAQ’s

These are my typical answers to some typical questions surrounding HTML5:

Is HTML5 complete?

No, actually it’s not even a W3C recommendation yet, but it is “ready.”

Which browsers support HTML5?

All of them. The real question is: to what extent? You can always go here to test how much your browser REALLY supports HTML5.

So…Is Silverlight or Flash dead?

Right now, there’s a lot of buzz in the developer community that HTML5 can and will replace both Silverlight and Flash. That mindset may very well drive that perception toward reality.

That said, I haven’t found one person yet that can actually show me in HTML5 what I can’t do in Silverlight or Flash. I am enjoying getting more and more experienced with some of the cool stuff I can do with HTML5, though.

Are there user groups with an HTML5 focus?

Well, where I live (San Francisco) there is a rather large HTML5 Meet-up group with thousands of members that meets regularly. If nothing else, this shows an intense interest in the technology. It’s rare to see that kind of interest even in general group that spans twenty technologies.

If It Ain’t Broke…

For now, my recommendation is to keep using Flash or Silverlight or whatever is working for you…they are a long way from being considered “dated” technologies.

Conversely, don’t ignore where HTML5 is going and to wait to start using the new features. Some of your development and training effort should already be directed towards HTML5 – making sure that you’re not missing out on any opportunities for yourself or your clients.

I’d love to hear your comments and opinions. Where do you see these technologies in two, three, ten years?


With over 25 years of programming experience, Bruce Barstow, MCP, MCT, MCSD.Net, MCAD, CTTI has been providing technical training and consulting services in a wide range of technologies including programming, network engineering, internet/intranet, architectural mentoring, project-directed training and messaging solutions.

His early introduction to the computer science field allowed him the privilege of working on several key products including the Space Shuttle's post fight data analysis system, a prototype military electronic warfare detection software, the National Launch System, the American Launch System and the Soyuz Space program. He is also the author of VB.Net in 60 Minutes a Day.

Bruce currently instructs the following Learn iT! courses:

10267 - Intro to Web Development

10266 - Programming in C#

10550 - VB.Net in .Net 2010 

10263 - WCF

10265 - Data Access Solutions 

10262 - Windows Applications

10175 - Applications for SharePoint 2010