Auto refresh page every 30 seconds

If you want refresh the page you could use like this, but refreshing the page is usually not the best method, it better to try just update the content that you need to be updated.

javascript:

<script language="javascript">
setTimeout(function(){
   window.location.reload(1);
}, 30000);
</script>

There are multiple solutions for this. If you want the page to be refreshed you actually don't need JavaScript, the browser can do it for you if you add this meta tag in your head tag.

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

The browser will then refresh the page every 30 seconds.

If you really want to do it with JavaScript, then you can refresh the page every 30 seconds with Location.reload() (docs) inside a setTimeout():

window.setTimeout( function() {
  window.location.reload();
}, 30000);

If you don't need to refresh the whole page but only a part of it, I guess an AJAX call would be the most efficient way.

Just a simple line of code in the head section can refresh the page

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

although its not a javascript function, its the simplest way to accomplish the above task hopefully.