Which Browsers support WebXR?
Different browsers are implementing and WebXR APIs in different timeframes. Currently Chrome and new Edge browsers have WebXR APIs turned on as default and some of the features are under experimental flags.
Check browser support at CanIUse.com
You can turn on experimental flags by navigating to chrome://flags/ or edge://flags/ and searching for the experimental flag you are looking to enable and choosing enable from the drop down menu.