How to set an interval, but then stop it after 20 minutes

Question

Currently on my webpage I have a timer that runs a function every 30 seconds:

setInterval("someFunction(userId)", 30000);

This works fine, but the problem is if 100's of users leave their browser open (say when they go for lunch), it will poll our system and increase the load on our servers for no reason.

How can I stop this timer from running after say 20 minutes?

Don't use a string as the first parameter of `setInterval` or `setTimeout` — Andreas, Oct 17 '12 at 16:13
@Quentin what's wrong with the string? It is working fine now? — loyalflow, Oct 17 '12 at 16:21
See [Is there ever a good reason to pass a string to setTimeout?](http://stackoverflow.com/questions/6081560/is-there-ever-a-good-reason-to-pass-a-string-to-settimeout) — Quentin, Oct 17 '12 at 16:32

score 14 · Accepted Answer · answered Oct 17 '12 at 16:12

14

Just set timeout for 20 minutes to clear the interval:

var interval = setInterval(function() {
    someFunction(userId);
}, 30000);

setTimeout(function() {
    clearInterval(interval);
}, 1000 * 60 * 20);

answered Oct 17 '12 at 16:12

VisioN

143,310
32
282
281

2

I suggest to incorporate event listeners in the code, because otherwise the code just stops running after 20 minutes, even if the user is actively using the site. – Rob W Oct 17 '12 at 16:15

score 2 · Answer 2 · answered Oct 17 '12 at 16:14

When you call setInterval, you get a value returned, which is a handle to the running interval.

So the solution is to schedule another closure, which will prevent this interval from running:

var interval = setInterval("someFunction(userId)", 30000);  
setTimeout(function(){ clearInterval(interval) }, 20 * 60 * 1000);

score 0 · Answer 3 · answered Oct 17 '12 at 16:14

0

Set your interval as a variable.

Set another timer to reset that interval, or set a disable flag for your polling script after 20mins.

answered Oct 17 '12 at 16:14

Bryan Allo

696
3
9

score 0 · Answer 4 · answered Oct 17 '12 at 16:14

0

Try this:

var intervalId= setInterval(function(){
   someFunction(userId);
 }, 30000); 

setTimeout(function(){
   clearInterval(intervalId);
},20*60*1000);

setInterval returns an intervalId that you can use to pass to clearInterval later on.

answered Oct 17 '12 at 16:14

Abe Miessler

82,532
99
305
486

How to set an interval, but then stop it after 20 minutes

4 Answers4

Linked

Related