How to clearInterval with unknown ID?

Question

Say someone (evil) has set us a timer with setInterval, but we don\'t know its ID (we don\'t have the reference to the object, that setInterval is returning, no

Answer 1

I tried the approach suggested by #Shadow Wizard and it worked in clearing the interval. However, this approach had side effects afterwards. In my particular case, I was unable use jquery.fadeTo() after clearing all of the intervals.

The approach that I settled on is a cleaner solution, which is to redefine the setInterval method and save the interval ids in the re-defined methods. As shown here, I put the the ids into an array and then clear all of them. With a little more refinement of the structure to store the arrays, you could label them and clear them selectively.

var intervalTracking = new Array();
var intervalCount=0;

window.oldSetInterval = window.setInterval;
window.setInterval = ( function(func, interval) {
    var interval = oldSetInterval(func, interval);
    intervalTracking[++intervalCount]=interval;
    return interval;
});

function clearAllIntervals() {
    for (var i = 0 ; i <= intervalCount ; i++) {
    window.clearInterval( intervalTracking[i] );
    }
}

This seems to work!

Answer 2

I solved it by using localstorage, saving there the id of the setInterval, and picking up it later in order to clear that interval..

Answer 3

From quick test, all major browsers (latest Chrome, Firefox and IE) give pretty small numbers as the ID so just looping "blindly" over all possible numbers should work just fine:

function ClearAllIntervals() {
    for (var i = 1; i < 99999; i++)
        window.clearInterval(i);
}

Full example:

window.onload = function() {
    window.setInterval(function() {
        document.getElementById("Tick").innerHTML += "tick<br />";
    }, 1000);
    window.setInterval(function() {
        document.getElementById("Tack").innerHTML += "tack<br />";
    }, 1000);
};

function ClearAllIntervals() {
    for (var i = 1; i < 99999; i++)
        window.clearInterval(i);
}

#Placeholder div { width: 80px; float: left; }

<button type="button" onclick="ClearAllIntervals();">Clear All</button>
<div id="Placeholder">
    <div id="Tick"></div>
    <div id="Tack"></div>
</div>

This will stop all intervals, can't stop specific interval without knowing its ID of course.

As you can test for yourself, it should work on all major browsers mentioned above.

Answer 4

Well, empirically trials in Chrome show that setInterval returns a number which increments for each call. So if you are SURE that you setInterval was the last one set the following would work :

function clearLastInterval () {
  var i = setInterval (function () {}, 10000);
  clearInterval (i-1);
  clearInterval (i);
}

I'm not sure I would recommend this though ;-)