[vectorEQ]

there's so many frameworks etc to create interfaces, in so many languages..

this is made mostly in JS so it runs clientside / offline (i think that would be the motivation to do it in js).

click view source in the browser :-) or 'inspect' if you use chrome, and look into the .js files which you find from there.

Should get you on your way :)

though if you are server side developer, maybe php is more interesting as it processes on server side and will be easier to interact with your server side developments

css language is used for style related things in any case (where elements might be generated from code like js or php, but css still reflects the style in the browser)