HTML Document File : jetest.html

<div id="out">output</div>
<script>
var da=document.all,t1=[8,40,0],t2=[8,50,0]
function rep(){
var d,p,tot
d=new Date()
p=(d.getHours()-t1[0])*3600+
(d.getMinutes()-t1[1])*60+
(d.getSeconds()-t1[2])
tot=(t2[0]-t1[0])*3600+(t2[1]-t1[1])*60+(t2[2]-t1[2]) //24*60*60
da.out.innerText=Math.round(p/tot*10000)/100+"%"
}
setInterval(rep,500)
</script>

<div style="text-align: center">centered</div>
<b>bold</b> <i>italic</i> <u>underlined</u>