revision:
<div class="spec grid">
<div id="digital" class="clock" onload="showTime()"></div>
<div id="digital-1" class="clock"></div>
<div id="digital-2" class="clock"></div>
<div id="digital-3" class="clock"></div>
</div>
<style>
.clock{position: relative; width: 30vw; height: 3vw; border: 0.2vw solid darkgrey;
background-color: lightgrey; color: blue; padding: 1vw;}
#digital {position: relative; top: 5%; left: 0%; color: black; font-size: 2vw;
font-family: 'Righteous', cursive;letter-spacing: 0.1vw;}
#digital-1 {position: relative; top: 5%; left:0%; color: blue; font-size: 2vw;
font-family: 'Righteous', cursive;letter-spacing: 0.1vw;}
#digital-2 {position: relative; top: 5%; left:0%; color: white; font-size: 2vw;
font-family: 'Righteous', cursive;letter-spacing: 0.1vw;}
#digital-3 {position: relative; top: 5%; left:0%; color: red; font-size: 2vw;
font-family: 'Righteous', cursive;letter-spacing: 0.1vw;}
</style>
<script>
function showTime(){
var date = new Date();
var h = date.getHours();
var m = date.getMinutes();
var s = date.getSeconds();
var shanghai = date.getHours();
var tokyo = date.getHours()+1;
var brussels = date.getHours()-7;
var london = date.getHours()-8;
var session = "AM";
if(h == 0){ h = 12; }
if( h > 12){ h ; session = "PM"; }
if(tokyo > 12){ h ; session = "PM"; }
if(brussels > 12){ h ; session = "PM"; }
if(london > 12){ h ; session = "PM"; }
h = (h < 10) ? "0" + h : h;
m = (m < 10) ? "0" + m : m;
s = (s < 10) ? "0" + s : s;
var time = h + ":" + m + ":" + s + " " + session;
var tokyo_time = tokyo + ":" + m + ":" + s + " " + session;
var brussels_time = brussels + ":" + m + ":" + s + " " + session;
var london_time = london + ":" + m + ":" + s + " " + session;
document.getElementById("digital").innerText = "Shanghai: " + time;
document.getElementById("digital-1").textContent = "Tokyo: " + tokyo_time;
document.getElementById("digital-2").innerText = "Brussels: " + brussels_time;
document.getElementById("digital-3").textContent = "London: " + london_time;
setTimeout(showTime, 1000);
}
showTime();
</script>