If I understand you correctly and you're trying to use Node.js module system in browsers, that won't work. Browsers doesn't implement such features natively. Script files can only be included to the page with script tags or some kind of ajax system that fetches the files from the server. There are few such a libraries that provide such a functionalities.
RequireJS might be what you're looking for the client side though.
RequireJS is a JavaScript file and module loader. It is optimized for in-browser use, but it can be used in other JavaScript environments, like Rhino and Node. Using a modular script loader like RequireJS will improve the speed and quality of your code.
Also note that some of the Node.js features are not possible in the browsers. For example the direct file system access is not possible in the browsers, it would be a huge security risk. Most javascript modules that provide both server and client side functionalities explicitly mentions it and provide separate script files for both sides.
Also if you only want to send coordinate data from the server to the client, then it might be good to use Ajax or WebSocket to send the data in a JSON format.