Does the browser keep track of active timer IDs?

Question

Does the browser keep track of active setInterval and setTimeout IDs? Or is this solely up to the developer to keep track of?

If it does keep t

Answer 1

Update:

There are 2 aspects to this question.

1. Does the browser keep track of timer IDs?
2. Are they accessible

I can only presume for #1 (and later #2) that the OP means "are they tracked" in the general sense because as a Developer s/he would like control over them.

In short, yes they are tracked (as @s_hewitt noted, as long values by the browser) and they can be managed by the developer by maintaining a reference to the timers when setup.

As a developer you can control (e.g. stop) them by calling (clearInterval(handleRef), or clearTimeout(handleRef))

However there is no default window.timers or similar collection that gives you a list of the existing timers - you will need to maintain that yourself if you feel you need to.

function startPolling(delay){
  pollHandle = setInterval(doThis, delay);
}
function stopPolling(){
  clearInterval(pollHandle);
}

function doThisIn30minUnlessStopped(){
  timerHandle = setTimeout(doThisThing, 1800000);
}
function stop30minTimer(){
  clearTimeout(timerHandle);
}    

You simply need to create a variable reference to your timer, and if/when needed, clear it by name.

When you load another page, all the timers are automatically cleared by the browser so you don't need to maintain a handle, and clear them unless you need/want to.