This question is, I suppose, not limited to Javascript, but it is the language I use to create my game, so I'll use it as an example.

For now, I have structured my HTML5 game like this:

var fps = 60;
var game = new Game();

setInterval(game.update, 1000/fps);

And game.update looks like this:

this.update = function()
{
    this.parseInput();
    this.logic();
    this.physics();
    this.draw();
}

This seems a bit inefficient, maybe I don't need to do all of those things at once. An obvious alternative would be to have more intervals performing individual tasks, but is it worth it?

var fps = 60;
var game = new Game();

setInterval(game.draw, 1000/fps);
setInterval(game.physics, 1000/a); //where "a" is some constant, performing the same function as "fps"
...

With which approach should I go and why? Is there a better alternative? Also, in case the second approach is the best, how frequently should I perform the tasks?