script.js

var CDown = function() {
	this.state=0;// if initialized
	this.counts=[];// array holding countdown date objects and id to print to {d:new Date(2013,11,18,18,54,36), id:"countbox1"}
	this.interval=null;// setInterval object
}

CDown.prototype = {
	init: function(){
		this.state=1;
		var self=this;
		this.interval=window.setInterval(function(){self.tick();}, 1000);
	},
	add: function(date,id){
		this.counts.push({d:date,id:id});
		this.tick();
		if(this.state==0) this.init();
	},
	expire: function(idxs){
		// for(var x in idxs) {
		// 	this.display(this.counts[idxs[x]], "Now!");
		// 	this.counts.splice(idxs[x], 1);
		// }
	},
	format: function(r){
		var pre='',post='',divide=', ',
			out="";
		if(r.d != 0){out += pre+r.d +" "+((r.d==1)?"day":"days")+post+divide;}
		if(r.h != 0){out += pre+r.h +" "+((r.h==1)?"hour":"hours")+post+divide;}
		out += pre+r.m +" "+((r.m==1)?"min":"mins")+post+divide;
		out += pre+r.s +" "+((r.s==1)?"sec":"secs")+post+divide;

		return out.substr(0,out.length-divide.length);
	},
	math: function(work){
		var	y=w=d=h=m=s=ms=0;

		ms=(""+((work%1000)+1000)).substr(1,3);
		work=Math.floor(work/1000);//kill the "milliseconds" so just secs

		y=Math.floor(work/31536000);//years (no leapyear support)
		w=Math.floor(work/604800);//weeks
		d=Math.floor(work/86400);//days
		work=work%86400;

		h=Math.floor(work/3600);//hours
		work=work%3600;

		m=Math.floor(work/60);//minutes
		work=work%60;

		s=Math.floor(work);//seconds

		return {y:y,w:w,d:d,h:h,m:m,s:s,ms:ms};
	},
	tick: function(){
		var now=(new Date()).getTime(),
			expired=[],cnt=0,amount=0;

		if(this.counts)
		for(var idx=0,n=this.counts.length; idx<n; ++idx){
			cnt=this.counts[idx];
			amount=cnt.d.getTime()-now;//calc milliseconds between dates

			// if time is already past
			if(amount<0){
				expired.push(idx);
			}
			// date is still good
			else{
				this.display(cnt, this.format(this.math(amount)));
			}
		}

		// deal with any expired
		if(expired.length>0) this.expire(expired);

		// if no active counts, stop updating
		if(this.counts.length==0) window.clearTimeout(this.interval);
		
	},
	display: function(cnt,msg){
		document.getElementById(cnt.id).innerHTML=msg;
	}
};


function getMobileOperatingSystem() {
    var userAgent = navigator.userAgent || navigator.vendor || window.opera;

    // Windows Phone must come first because its UA also contains "Android"
    if (/windows phone/i.test(userAgent)) {
        return "Windows Phone";
    }

    if (/android/i.test(userAgent)) {
        return "Android";
    }

    // iOS detection from: http://stackoverflow.com/a/9039885/177710
    if (/iPad|iPhone|iPod/.test(userAgent) && !window.MSStream) {
        return "iOS";
    }

    return "unknown";
}


window.onload=function(){
	var cdown = new CDown();

	cdown.add(new Date(2021,8,30,18,00,00), "countdown");
    // cdown.add(new Date(2021,8,23,18,53,00), "countdown");

    let device = getMobileOperatingSystem();
    if (device == "Android") {
        document.getElementById('calendar').href="https://calendar.google.com/event?action=TEMPLATE&tmeid=N25xbTJndGltNThvNWk0Njc1MW91ODE4MWogaUBhbmFuYXlhcm9yYS5jb20&tmsrc=i%40ananayarora.com";       
    } else {
        document.getElementById('calendar').href="infosession.ics";
    }

};