Now that the library is open source, developers can use it to build and design Windows-like Web applications for other browsers and platforms, including Chrome, Firefox, Android, and iOS.
Such cross-platform capability could save developers time by eliminating the need to code the same app multiple times for non-Windows platforms and browsers other than Internet Explorer, according to the company.
"We're really not interested in having a Microsoft's version of another thing you already have. ... Our goal is to contribute something new, to solve actual problems people have," said Paul Gusmorino, a principal program manager lead on the team responsible for user interface platforms in Windows, in a WinJS session at the Microsoft Build developer conference this week in San Francisco.
The library features components that can help build the infrastructure of a Web app, such as data binding. It also offers advanced user interface controls and designs such as ListView, FlipView, animations, and semantic zoom.
Microsoft offers demonstrations of the various features, along with their implementation code, on the WinJS Preview website.