Успех, кому нужно
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<script>
window.addEventListener('DOMContentLoaded', function() {
function refresh()
{
[].forEach.call( document.querySelectorAll('.timer'), function(el) {
var sec = +el.dataset.sec;
if(sec==-1){sec=el.dataset.sec=59; el.dataset.min--;}
var min = +el.dataset.min;
if(min==-1){min=el.dataset.min=59; el.dataset.chas--;}
var chas = +el.dataset.chas;
if(sec<=9){sec="0" + sec;}
time=(chas<=9 ? "0" + chas : chas) + ":" + (min<=9 ? "0" + min : min) + ":" + sec;
el.innerHTML=time;
if(+sec||+min||+chas) el.dataset.sec--;
});
setTimeout(refresh, 1000);
}
refresh()
});
</script>
</head>
<body>
<span class="timer" data-chas="01" data-min="01" data-sec="05"></span><br>
<span class="timer" data-chas="00" data-min="01" data-sec="05"></span>
</body>
</html>