A brief history -
Conceived in the fall of 2007, with the vision of becoming the go-to development platform for cross browser and OS compatibility, Microsoft created Silverlight as a free plug-in development tool to foster a new level of interactivity for Web and mobile applications. One of the largest reasons for Silverlight’s previous success may be attributed to its support for rich UI features such as animations, graphics and visual media, as it was created to include a subset of WPF.
An unclear future -
In the spring of 2015 Microsoft announced that it will be officially dropping support for Silverlight starting with its new Edge browser and has entered maintenance mode for the platform in Internet Explorer 11 with the official retirement of Silverlight projected for 2021 - as far as Microsoft is concerned, Internet Explorer 11 is the last and only version of the browser that will support Silverlight.
The writing is on the wall - Silverlight is no longer the answer to superior cross-browser support and is significantly less viable as a web-browser technology in this regard, with support phased out or in the process of - with virtually all conventional browsers opting for the more secure, both architecturally and in regard to market share, (read future proof) HTML5.
Flash forward to 2016 and it's clear to most, that the platform, having long entered its twilight phase is close to moribundity.
Netflix has executed its plan for phasing out support for the latest Silverlight 5 iteration in favor of HTML5’s premium video extensions, with the platform being particularly well suited for web content delivery across a wide span of mobile devices, this same trend can be seen with other major video sharing and streaming services, such as Youtube, Dailymotion and Vimeo; plugless browsing really does appear to be the wave of the future.
Technology giant Google, dropped support for Silverlight indirectly by its Google Chrome browser, a result of its deprecation of NPAPI support; this decision single handedly shifted the landscape of silverlights availability to consumers with Google Chrome comprising 48.65% of all browsers in use as of the date of this writing in July, 2016, (http://www.netmarketshare.com/browser-market-share.aspx?qprid=0&qpcustomd=0).
The potential benefits of HTML5 are many and include a single solution - offering support for all of today’s most popular platforms such as Windows, Android, Mac and iOS; allowing for greater flexibility for developers, access to a larger potential client base by which their applications may be used, a more consistent experience and potentially vastly shorter overall time between conception and deployment and we didn’t even touch on its rich UI features.
HTML5 enables you to incorporate the very rich UI features that made Silverlight successful, doing it all without ever requiring consumers to download a single plugin; including support for animations, embedded visual and audio media, gesture support and an ever improving video streaming potential.
Closing words - Rest in peace, Silverlight - move along, there’s nothing to see here, folks
In all seriousness though, it's clear that HTML5 is here to stay and ultimately allows you to create rich visually appealing applications that Silverlight enabled you to build previously, and did I mention being a single multi-platform solution?
For the time-being, there may be an argument for continuing to rely on Silverlight in certain scenarios and the platform may remain a viable option for legacy apps running OOB, but with Microsoft essentially entering maintenance mode with the platform, having expressed publicly that no new development efforts will be made, (rather focusing efforts on their new Edge browser, which in itself marks the end of conventional browser support for SL in Microsoft's lineup) application development potential here too is doomed to stagnate, at least eventually.
If you are interested in building dynamic interfaces with the intention of it lasting longer than the next model of Windows Phone, then HTML5 is the way to go. Microsoft has provided us with its stance, officially supporting Silverlight until 2021, but the fact of the matter is that it will only be usable by what will very soon be legacy OS and web browsers.
Have you recently started development or are maintaining an application using Silverlight? if staying on the cutting edge and ensuring a future proof solution for cross platform apps is important to you, it may be wise to invest in a viable migration strategy, perhaps using HTML5 as a robust, secure and arguably future proof alternative; check out this blog for recommended migration strategies:
Why you need a Silverlight Migration Strategy