I have the same problem, so
After finishing XAMPP installation, where no eerors or warnings were prompted, and tried to fix ports, 80 to 8082 and 443 to 44343. I was not have any contact with the Server, coming back to ports 80 and 443, I was able to run localhost/xampp and localhost/phpmyadmin. Then made a NEW folder (testfolder) into htdocs directory and tried to connect to a table in mariaDB by name mytesttable. with a script like this:
<title>
<html>
<head>
</body>
HTML SECTION
<?php
db_name = 'test";
db_usr = 'root';
db_pass = 'root's password';
echo ("this is php section');
.......Connection commands......
echo ('end of php section');
/?php>
END OF HTML
</body>
</html>
the PHP section is completely ignored in my case no matter how many times I tried.
Pls advise me.