index.js

function getTimeStamp() {
	var now = new Date();
	return ((now.getMonth() + 1) + '-' + (now.getDate()) + '-' + now.getFullYear() + " " + now.getHours() + ':' + ((now.getMinutes() < 10) ? ("0" + now.getMinutes()) : (now.getMinutes())) + ':' + ((now.getSeconds() < 10) ? ("0" + now.getSeconds()) : (now.getSeconds())));
	//in Chrome, this returns: Fri Sep 04 2015 14:10:50 GMT-0400 (EDT)
	//in Firefox, this returns: Date 2015-09-04T18:11:08.322Z
}
//What's the correct way to get the Firefox one to display correctly? In the bigger picture, this is used in a ticketing system
//and the duration of the ticket is sent in an email. 
//If the ticket is closed in Chrome, no problems: it shows the duration correctly.
//If the ticket is closed in Firefox, it returns NaN

millisToTime = function(ms){
	x = ms / 1000;
	seconds = Math.round(x % 60);
	x /= 60;
	minutes = Math.round(x % 60);
	x /= 60;
	hours = Math.round(x % 24);
	x /= 24;
	days = Math.round(x);
	// return {"Days" : days, "Hours" : hours, "Minutes" : minutes, "Seconds" : seconds};
	return days + " days, " + hours + " hours, " + minutes + " minutes, and " + seconds + " seconds";
}

$("#close-ticket").click(function(e){
	e.preventDefault();
	var gts_format = new Date(getTimeStamp());
	var js_date = new Date("<?php echo $format_time_submitted; ?>");
	var ticket_duration = (gts_format - js_date);
	var ticket_duration_formatted = millisToTime(ticket_duration);
});