How to reload page every 5 seconds?

For auto reload and clear cache after 3 second you can do it easily using javascript setInterval function. Here is simple code

$(document).ready(function() {
  setInterval(function() {
    cache_clear()
  }, 3000);
});

function cache_clear() {
  window.location.reload(true);
  // window.location.reload(); use this if you do not remove cache
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<p>Auto reload page and clear cache</p>

and you can also use meta for this

<meta http-equiv="Refresh" content="5">

To reload the same page you don't need the 2nd argument. You can just use:

 <meta http-equiv="refresh" content="30" />

This triggers a reload every 30 seconds.

 <meta http-equiv="refresh" content="5; URL=http://www.yourdomain.com/yoursite.html">

If it has to be in the script use setTimeout like:

setTimeout(function(){
   window.location.reload(1);
}, 5000);