UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:51.0) Gecko/20100101 Firefox/51.0

Steps to reproduce the problem:
execute code that sets a timer

What is the expected behavior?
the timer goes off and does something

What went wrong?
I am the developer for a private corporate site that allows contractors spread over a wide geographic area to interact with the corporate server.  The work is task-based.  The contractors  are presented with a list of available tasks and after selecting one, download a file.  After completing the task, they upload the results of their effort and payment is made.

The Job Queue, the list of available tasks, is the central screen of this operation.  It lists the available jobs and the contractors select the one they want to work on. Due to competition between them, fast refresh of the job queue is critical, since the tasks are added to the list on an irregular schedule. There is a feeding frenzy when new jobs appear.  So the contractors are allowed to set a timer with an interval as brief as 20 seconds, refreshing the screen on every timeout. At least that way they are on an equal footing, though it's still every man for himself.

This has been going on since 1999, though the traffic is much greater now.

Suddenly, the timer stopped working on Chrome.  It appears to be because of the latest version.  A contractor told me his auto refresh stopped working, and he had to do manual refresh to see the new jobs.  In order to diagnose the problem, I checked the version of my own Chrome with About, so I could compare with his.  To my horror, it did an automatic upgrade of Chrome without asking me. (That's a problem in itself; I usually allow a burn-in time for new versions, just because of crap like this. I'm not sure if I'll ever click on About again.) So now my timer refresh doesn't work either.  I can set the interval as always, but there is no refresh---ever.  The timer either doesn't start at all, or it doesn't operate correctly on completion.

Here is the code that operates the timer:

function setrefreshrate (the_form)
{
  var m, seconds, nsecs;

  // Decode what they entered

  seconds = the_form.howoften.value;
  if (seconds > '') {
    nsecs = parseInt (seconds);
    if (isNaN (nsecs) || (nsecs <= 0)) {
      window.alert ('Please give a positive number of seconds, or leave empty for no refresh');
      the_form.howoften.value = '';
      the_form.howoften.focus ();
      return (false);
    }
    if (nsecs < 20) {
      window.alert ('The number of seconds cannot be less than 20');
      the_form.howoften.value = '20';
      seconds = '20';
    }
  }
  the_form.howoften.blur ();

  // Set the cookie to what they entered (or what we modified it to)

  setcookie (seconds);

  // Stop the old timer

  if (oldtimerid != null) {
    clearTimeout (oldtimerid);
    oldtimerid = null;
  }

  // Start the new timer going

  if (seconds == '') window.alert ('Page will not be automatically refreshed');
  else {
    m = 'Page will be refreshed every ' + seconds + ' seconds';
    window.alert (m);
    startrefreshtimer (the_form);
  }

  // Don't really do a submit

  return (false)
}

function startrefreshtimer (the_form)
{
  var cookies, i, j, seconds;

  cookies = document.cookie;

  i = cookies.indexOf (cookie_name);
  if (i >= 0) {
    j = cookies.indexOf (';', i);
    if (j < 0) j = cookies.length;
    seconds = cookies.substring (i + cookie_name.length, j);
    the_form.howoften.value = seconds;
    if (seconds > '')
        if (parseInt (seconds) < 20) {
            the_form.howoften.value = '20';
        }
    if (seconds > '') {
      setcookie (seconds);
      oldtimerid = setTimeout ('window.location.reload ()', parseInt (seconds) * 1000);
    }
  }
}

Slightly complicated setting up the timer, but the actual refresh isn't.

Again, was working fine and then minutes later, after the upgrade(?!), stone dead.

I single stepped through all this stuff with the debugger.  No errors reported, all values looked correct (such as seconds).  Whatever happened (or didn't happen) was apparently in the library routine setTimeout.

The contractors depend on the timer.  If this isn't resolved quickly, they will go to firefox and forget chrome ever existed.  And firefox does not have this problem, another indication my code is not to blame.

Did this work before? Yes not sure, "about" foolishly did an automatic upgrade when I tried to determine my version; i didn't get a chance to note the old one

Chrome version: Version 56.0.2924.76 (64-bit)  Channel: n/a
OS Version: OS X 10.10
Flash Version: Shockwave Flash 24.0 r0

The automatic upgrade in "about" is another unrelated problem.  I want to decide for myself when to upgrade. Because of problems like the timer failure.