How do I set a refresh interval on a dashboard page?

Create a user defined page named refresh.html with this code:

<script>
  setTimeout(function(){
     parent.location.reload(1);
  }, 5000);
</script>

Then place the page on the bottom of your application dashboard using the web page widget option. You can adjust the timer (5000 milliseconds) to suit your needs. The reason to put it at the bottom is to not overtake the information currently displayed on the dashboard.