Are you able to send me a live link/URL to your search page so I can take a look?

Hi

I can see that you are using the ‘As an Archive’ method, which relies on your theme template file, which you will have specified.

As the Ajax refresh is looking for a container with the ID of article_container, the template must have its ‘No Results Found` message inside a same named container, which means you would have to edit the template file. To do that safely, you must be working with a child theme and have the edited file in the child theme folder.

You are opening the Ajax container outside the start of the IF:

echo '<div id="article_container">';
if (have_posts()) { ?>

But then you end it INSIDE the IF and echo the HTML content there:

}// end while
$html_content .='</div>'; //article-container
echo $html_content; ?>

<?php } else { ?>
<!– Why we never come here?! –>
<?php echo 'no-results'; ?>
<?php } // endif; ?>

Instead try this (but keep a copy of your code):

}// end while

<?php } else { ?>
<!– Why we never come here?! –>
<?php $html_content = 'no-results'; ?>
<?php } // endif; ?>
$html_content .='</div>'; //article-container
echo $html_content; ?>

And, strictly speaking, this line:

echo '<div id="article_container">';

Should be:

$html_content = '<div id="article_container">';

I think.

I wonder. You are constructing the html before you output the form and ajax container, but that part does not get output again.

Instead of adding each part to the $html_content string, why not echo it directly?