Make HTML5 video stop at indicated time

TL;DR: Simply listen on "timeupdate":

video.addEventListener("timeupdate", function(){
    if(this.currentTime >= 5 * 60) {
        this.pause();
    }
});

---

The usual way to wait for something in JavaScript is to wait for an event or a timeout. A timeout is out of question in this case, the user might pause the video on his own. In this case the stop wouldn't be on your specific time, but earlier.

Checking the time regularly is also too costly: you either check too often (and therefore waste precious processing power) or not often enough and therefore you won't stop at the correct time.

However currentTime is a checkable property, and to our luck, there's the timeupdate event for media elements, which is described as follows:

The current playback position changed as part of normal playback or in an especially interesting way, for example discontinuously.

This concludes that you can simply listen on timeupdate and then check whether you've passed the mark:

// listen on the event
video.addEventListener("timeupdate", function(){
    // check whether we have passed 5 minutes,
    // current time is given in seconds
    if(this.currentTime >= 5 * 60) {
        // pause the playback
        this.pause();
    }
});

Keep in mind that this will pause whenever the user tries to skip past 5 minutes. If you want to allow skips and only initially pause the video beyond the 5 minute mark, either remove the event listener or introduce some kind of flag:

var pausing_function = function(){
    if(this.currentTime >= 5 * 60) {
        this.pause();

        // remove the event listener after you paused the playback
        this.removeEventListener("timeupdate",pausing_function);
    }
};

video.addEventListener("timeupdate", pausing_function);

The timeupdate event is what you are looking for, but it only fires at about 2 fps which is too slow to stop at precise times.

For those cases I used requestAnimationFrame which fires at 60 fps and decreased the endTime a little which fixes small "lag hops":

const onTimeUpdate = () => {
    if (video.currentTime >= (endTime - 0.05)) {
      video.pause()
    } else {
      window.requestAnimationFrame(onTimeUpdate)
    }
}
window.requestAnimationFrame(onTimeUpdate)