Node.js is a multi-authority supported(websockets,network protocols, Rest Api, HTTP/TCP communications) and cross browser compatible architecture.

since it is supported on so many layers of connections and communications, the architecture manages to host several web servers, either if it is installed locally on machine, the machine becomes a host to the computational code and logics written on the architecture of node by the user, the host on the machine in this case is "BROWSER".

However there are several more node compatible platforms which replaces the local machine support by the browsers, you can write and install node on GITHUB PAGES and make your node server which is now supported and managed by the node packages and libraries installed by github servers itself.