A good start for anyone getting into js coding is to use a lint tool. It will help you keep your code tidy and professional, as well as use good practices. You need to be heading in a good direction though. As far as cameras go, you can either define a simple x, y position in the world, and just offset your tiles by this. You can also give it a width and height to know how many tiles fit in a camera's frustum. There are many approaches but starting there might be easiest.
Have you considered using a HTML5 canvas rendering engine? There are many out there and will help you get started with rendering sprites and normal game things.
I encourage you to spend time and look at a few different operating systems, APIs and development environments in general. I found love with OpenGL and KDevelop on KDE in Linux (Kubuntu). I haven't looked back in quite a while. I keep my engine/games cross platform so they'll run on Windows, OSX and Linux though, just for good form.