We keep on hearing about the metaverse but what is it and more importantly, can JS be used to build it? We'll briefly clarify what the metaverse is and give practical examples today with federated virtual reality servers managed by different persons. Behind the buzzword from Facebook/Meta there is a truly interesting concept : connecting virtual worlds! To do so there is no need to be one of the largest advertising company. In fact there are several solutions working today allowing to navigate from 3D or VR web pages and even keep information across, like a profile. During this presentation we will explore the WebXR specifications, in particular links between pages, and test an implementation running today named ImmersSpace based on Mozilla Hubs and ActivityPub.