How to refresh page on specific day at specific time in specific time zone?

Question

I am developing a website that has two back to back web broadcasts. I have used PHP to display the time that the buttons should be enabled and disabled. Now I need to use Javascript to automatically refresh the page before the first broadcast, before the second broadcast and after the second broadcast. I implemented the following script and it does refresh the page at the given time, however, it doesn't work exactly as I need it to. I need to alter the script so that it refreshes the page on Sundays at 7:45pm, 8pm and 8:30pm EST only.

I'm using a modified script from this answered question

function refreshAt(hours, minutes, seconds) {
var now = new Date();
var then = new Date();

if(now.getUTCHours() > hours ||
   (now.getUTCHours() == hours && now.getUTCMinutes() > minutes) ||
    now.getUTCHours() == hours && now.getUTCMinutes() == minutes && now.getUTCSeconds() >= seconds) {
    then.setUTCDate(now.getUTCDate() + 1);
}
then.setUTCHours(hours);
then.setUTCMinutes(minutes);
then.setUTCSeconds(seconds);

var timeout = (then.getTime() - now.getTime());
setTimeout(function() { window.location.reload(true); }, timeout);
}

Then I call the refreshAt() function.

refreshAt(19,45,0); //Will refresh the page at 7:45pm
refreshAt(20,00,0); //Will refresh the page at 8:00pm
refreshAt(20,30,0); //Will refresh the page at 8:30pm

Where I get confused is how to alter this script to only implement the refresh for EST on Sundays.

Answer 1

I figured it out. Here's the script:

function refreshAt(hours, minutes, seconds, day) {
    var now = new Date();
    var then = new Date();
    var dayUTC = new Date();

    if(dayUTC.getUTCDay() == day) {

        if(now.getUTCHours() > hours ||
       (now.getUTCHours() == hours && now.getUTCMinutes() > minutes) ||
        now.getUTCHours() == hours && now.getUTCMinutes() == minutes && now.getUTCSeconds() >= seconds) {
        then.setUTCDate(now.getUTCDate() + 1);
        }

    then.setUTCHours(hours);
    then.setUTCMinutes(minutes);
    then.setUTCSeconds(seconds);


    var timeout = (then.getTime() - now.getTime());
    setTimeout(function() { window.location.reload(true); }, timeout);
    }
}

And then I just call the refreshAt() function:

 refreshAt(20,00,0,1); //Will refresh the page at 8:00pm on Monday UTC or 3:00pm EST

Answer 2

An alternative approach would be to use Pusher. This keeps an open connection to receiving events.

Include the Pusher javascript:

<script src="http://js.pusher.com/1.11/pusher.min.js"></script>

Bind to a pusher event of "refresh" with this code:

var pusher = new Pusher('abc123'); // Get a key when you sign up and replace this
var refreshChannel = pusher.subscribe('refreshing');
refreshChannel.bind('refresh', function(thing) {
  location.reload(true);
});

Then at 8pm (or whenever you want) manually issue a pusher event on the Pusher control panel page, and all of the people currently viewing the page would be reloaded.