WebVR 1.1 is available in Microsoft Edge beginning with the Windows 10 Creators Update as a developer unlock feature. Developers can now use this API to create immersive VR experiences on the web.
The WebVR API provides HMD pose data to the page which can be used to render a stereo WebGL scene back to the HMD. Details on API support is available on the Microsoft Edge Platform Status page. The WebVR API surface area is present at all times within Microsoft Edge. However, a call to getVRDisplays() will only return a headset if the operating system has been placed in Developer Mode, and either a headset is plugged in or the simulator has been turned on.
Instructions for accessing WebVR content in your immersive headset can be found in the Enthusiast's Guide.