WebXR (as of 26th July 2018) is only available through Chrome Canary and an Android device running ARCore.
It is not ready for mass public consumption and will regular not work due to Google changing their systems. This is the warning from Google "Experimental - This release has not been tested. It may be unstable or fail to run at times. Recommended for developers and advanced users only. "
If you are ready to get your hands dirty this is how to see your Augmented Reality content on Plattar with WebXR, see below.
You will need to type into your Chrome Canary browser URL field chrome://flags
Disable WebVR (#webvr)
Enable WebXRDevice API (#webxr) and WebXR Hit Test (#webxr-hit-test)
Go to your Plattar account on your computer to get your 'App Code' eg. AC45
Visit http://cdn.plattar.com/webxr/index.html on your mobile in Chrome Canary enter your 'App Code'
Experience WebXR powered by Plattar!
We will update this as Google updates their information.