Question

I’m having trouble with fast forwarding a timer. It is very basic at this stadium. I have a interval that add numbers. Like this:

setInterval(function () {
    //+1 second
    //Format output to 00:00
    //Handle minute update
}, 1000);

This works perfect. The timer is going at normal speed. What I want to do is fast forwarding this timer. I want a timer minute to take 1 real second. I have tried:

setInterval(function () {
    //+1 second
    //Format output to 00:00
    //Handle minute update
}, 15);

That works sometimes and sometimes not. Sometimes it stops att 01:02 instead of 01:00. It may be my lack of math knowledge but I don’t know. How would you do it? I am going to stop and start the timer every “timer minute” so it’s important that the interval is correct.

EDIT
Here is a fiddle of how I want it to work: http://jsfiddle.net/tbleckert/pF4gs/

EDIT 2
Maybe I should just adjust the time when I stop the timer?

EDIT 3
It seems like 15 ms works most of the times. But something makes ut unreliable, I think the best way is to just adjust the time.

Answer 1

Ok so I’m going to answer this myself. I don’t think I was clear enough. When I start the timer a timeout starts at the same time, that after one second stops the timer. This is where it goes wrong, the timer doesn’t always show 01:00 when it stops.

So, the final solution is the set the seconds to 00 every time it stops, and because it all happens so fast, you wont notice.

setTimeout(function () {
  clearInterval(interval);
  $('.clock').html(rMin.slice(-2) + ':00');
}, 1000);

Check my updated fiddle:
http://jsfiddle.net/tbleckert/pF4gs/2/