Read the slides by Myles Borins for an introduction about Faust with Web Audio.
The minimal examples by Yosuke Torii are a good way to get started.
faust2webaudiowasm it is pretty easy to create self-contained HTML instruments.
They can run within any webserver.
The Sine Example
If we want to use Faust-built DSP elements in a more flexible way, there is another way which delivers
$ faust2wasm sine.dsp