You are adopting an approach I am not familiar with
Have you seen https://developers.google.com/custom-search/docs/element?
I usually think of it in two ways.
The first simple needs something like
var cx = '123:456'; // Insert your own Custom Search engine ID here
gcse.src = (document.location.protocol == 'https' ? 'https:' : 'http:') +
'//www.google.com/cse/cse.js?cx=' + cx;
var s = document.getElementsByTagName('script'); s.parentNode.insertBefore(gcse, s);
<!-- Place this tag where you want both of the search box and the search results to render -->
on the web page.
That been said I get the impression that results.php is being called correctly. This would suggest that something is wrong server side.
The query to google should be
but this does not return anything. It could be that the custom search is not configured correctly.
I would go into custom search and use the preview.