php files connected with mysql server not working -

i started php project in netbeans , connected database in localhost/phpmyadmin. on running gives error on browser..

enter image description here

why happen? how avoid it?

here codes in project.. dbconnect.php , index.php. files saved in /var/www/html/testing/ (testing name of project).

edit : tried url localhost/testing/index.php still gets same error. enter image description here

edit2 : folder structure of /var/www enter image description here

use path localhost/testing/index.php. remove html folder url.

reason ? linux default considers php files in html folder. no need give folder name in url.

Macro