Countdown Timer with Javascript (Repeating Weekly)

Here is the code I use to create a weekly repeating countdown timer. It works well, but I would like to expand on the following:

1. How can use this code twice on a single page without conflicts? Currently, copying all elements and adjusting the "expiry" doesn't work. I would like this to display two separate outputs with different expiry dates.

2. Output is in the following format: hours, mins, and seconds. How can it display only the most relevant information? For example, if there are 10 hours 12 minutes, and 10 seconds left, it would display: 10 hours only(excluding mins and seconds). Similarly, if there were 00 hours 00 minutes and 10 seconds left it would instead display: 10 seconds (excluding mins and hours). The same would go for minutes (excluding hours and seconds).

Any insight would be most appreciated.

Repeating Countdown Timer Javascript

<script>
var curday;
var secTime;
var ticker;
 
function getSeconds() {
 var nowDate = new Date();
 var dy = 1 ; //Sunday through Saturday, 0 to 6
 var countertime = new Date(nowDate.getFullYear(),nowDate.getMonth(),nowDate.getDate(),21,0,0); //20 out of 24 hours = 8pm
 
 var curtime = nowDate.getTime(); //current time
 var atime = countertime.getTime(); //countdown time
 var diff = parseInt((atime - curtime)/1000);
 if (diff > 0) { curday = dy - nowDate.getDay() }
 else { curday = dy - nowDate.getDay() -1 } //after countdown time
 if (curday < 0) { curday += 7; } //already after countdown time, switch to next week
 if (diff <= 0) { diff += (86400 * 7) }
 startTimer (diff);
}
 
function startTimer(secs) {
 secTime = parseInt(secs);
 ticker = setInterval("tick()",1000);
 tick(); //initial count display
}
 
function tick() {
 var secs = secTime;
 if (secs>0) {
  secTime--;
 }
 else {
  clearInterval(ticker);
  getSeconds(); //start over
 }
 
 var days = Math.floor(secs/86400);
 secs %= 86400;
 var hours= Math.floor(secs/3600);
 secs %= 3600;
 var mins = Math.floor(secs/60);
 secs %= 60;
 
 //update the time display
 document.getElementById("days").innerHTML = curday;
 document.getElementById("hours").innerHTML = ((hours < 10 ) ? "0" : "" ) + hours;
 document.getElementById("minutes").innerHTML = ( (mins < 10) ? "0" : "" ) + mins;
 document.getElementById("seconds").innerHTML = ( (secs < 10) ? "0" : "" ) + secs;
}
</script>

Call getSeconds() function to start timer with body onload

<body onload="getSeconds();">
    
    </body>

Timer Display HTML

<h6>Live in <span class="days" id="days"></span><span class="smalltext"> days,</span>
<span class="hours" id="hours"></span><span class="smalltext"> hours,</span>
<span class="minutes" id="minutes"></span><span class="smalltext"> minutes</span>
</h6>