Well, it looks my script is getting some sort of "ban" from the browser when it is trying to run some process in the loop. The script is running in the iframe, loaded from another domain and it's visible.

It is getting a ban only when running inside the iframe.

The code looks like this:

    app_cycle()
    {
        let self = this;

        // Making some fast things here (1-2 ms long)

        // Calculate the delay based on the real time value from (new Date())

        // Resulting "dt" is always between 5ms and 37ms. The ideal value is 20ms

        // Always remove old timer to avoid consecutive timers
        if (this.tickTimer) {
            clearTimeout(this.tickTimer);
            this.tickTimer = null;
        }

        this.tickTimer = setTimeout(() => {
            self.app_cycle();
        }, dt);
    }

So as you can see I am not making anything special, just the method app_cycle that runs each 20ms (it's relatively stable because I am recalculating dt according to external deviations to make the average frequency to 50 Hz).

The problem is: my application runs very slowly in the beginning. Right after page load, the setTimeout delays for 1000ms do not depend on the calculated dt value.

This situation longs for 65 seconds and then my application becomes running normally.

If I stop the application by closing an iframe with it and run it again (without reloading the parent main page), no 65-second delays occurred anymore.

After the main page reload I am getting the same delays.

It looks like something a "ban" from the browser (I've tested in Chrome and Firefox, same result) and the question HOW to avoid that ban.

Thank you very much!