Fatal error: Call to a member function query() on a non object

Question

I\'ve got this error:

Fatal error: Call to a member function query() on a non-object in /Applications/XAMPP/xamppfiles/htdocs/login.php on line 8

The line is

Answer 1

public function connectDB($DBServer, $DBUser, $DBPass, $DBName) {
            global $con;
            $con = new mysqli($DBServer, $DBUser, $DBPass, $DBName) or die ("Error occured");
            return $con;

and then pass $con in all the functions that you define or run wherever.