Try this:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
<script type="text/javascript">
function bed(){
var now = new Date();
var hr = now.getHours();
var targ = document.getElementById('time_alert');
targ.firstChild.nodeValue = (hr <= 23) ? hr+"00 Hours. You're good!!" : hr+"00 Hours. You need to go to bed";
setTimeout('bed()', 3600000);
}
onload = bed;
</script>
</head>
<body>
<span id="time_alert"> </span>
</body>
</html>
Or else have a look on following link for reference:
Refresh a page[
^]
Auto Postback or Refresh page for every defined time interval[
^]