I finally figured out how to move items: it's not by mouse cursor, but by dot in the middle of the screen T_T. Still no buttons though. My only problem now is camera control, which requires to Alt-Tab in and out of browser window.
I'm also getting this is browser console:
Failed to create agent because there is no valid NavMesh Lewd Cashier HTML.framework.js.gz:10:34712
Request for pointer lock was denied because Pointer Lock API is disabled by user preference. Lewd Cashier HTML.framework.js.gz:10:181325