Javascript Poll server. Will this cause a stack overflow?

Question

I am not too familiar with the specifics of every javascript implementation on each browser. I do know however that using setTimeout, the method passed in gets called on a separate thread. So would using a setTimeout recursively inside of a method cause its stack to grow indefinitely until it causes a Stack Overflow? Or would it create a separate callstack and destroy the current frame once it goes out of focus? Here is the code that I'm wondering about.

function pollServer()
{
    $.getJSON("poll.php", {}, function(data){
        window.setTimeout(pollServer, 1000);
    });
}

window.setTimeout(pollServer, 0);

I want to poll the server every second or so, but do not want to waste CPU cycles with a 'blocking loop' - also I do not want to set a timelimit on how long a user can access a page either before their browser dies.

EDIT

Using firebug, I set a few breakpoints and by viewing the "Script -> Stack" panel saw that the call stack is literally just "pollServer" and it doesn't grow per call. This is good - however, do any other implementations of JS act differently?

Answer 1

I am not sure if it would create a stack overflow, but I suggest you use setInterval if the period is constant.

This is how prototype implements its PeriodicalExecuter.

// Taken from Prototype (www.prototypejs.org)
var PeriodicalExecuter = Class.create({
  initialize: function(callback, frequency) {
    this.callback = callback;
    this.frequency = frequency;
    this.currentlyExecuting = false;

    this.registerCallback();
  },

  registerCallback: function() {
    this.timer = setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);
  },

  execute: function() {
    this.callback(this);
  },

  stop: function() {
    if (!this.timer) return;
    clearInterval(this.timer);
    this.timer = null;
  },

  onTimerEvent: function() {
    if (!this.currentlyExecuting) {
      try {
        this.currentlyExecuting = true;
        this.execute();
      } finally {
        this.currentlyExecuting = false;
      }
    }
  }
});