The uptake of HTML5 video playback has forced Microsoft to take the sword to Silverlight and leave it unsupported in its soon-to-be-released Edge web browser for Windows 10.

Microsoft said in a blog post that Silverlight will continue to be supported by the company, and the framework can still be used in IE 11 and out-of-browser applications, but that anyone relying on it for streaming media should move across to HTML5.

"[HTML5-based streaming] represents the most broadly interoperable solution across browsers, platforms, content, and devices going forward," the company said.

"Support for ActiveX has been discontinued in Microsoft Edge, and that includes removing support for Silverlight. The reasons for this ... include the emergence of viable and secure media solutions based on HTML5 extensions."

In May, Microsoft announced that ActiveX, VBScript, conditional comments, VML, browser helper objects, document modes, and IE 8 quirks mode would be discarded in Edge. It was anticipated that Silverlight would be among the technologies dropped.

"Both content providers and consumers will benefit from this transition," Microsoft said. "While the adoption of these technologies may present short-term challenges, the features and options discussed in this blog are provided to assist companies as they make this change."

The browser, formerly known as Spartan, will still allow extensions, with Skype, Reddit, and Pinterest being among those demonstrated in the past.

Edge will be the default browser for Windows 10 on PCs, tablets, and phones, with IE 11 being present on tablets and PCs for legacy websites.

In May, the company revealed that its integration of Mozilla's asm.js optimisations into its Chakra JavaScript engine had boosted Edge's JavaScript by over 300 percent.

The JavaScript performance improvements will also be available to Windows store apps written using HTML/CSS/JS and web views that target the EdgeHTML rendering engine in Windows 10.