you can try this solution

function getConnected($host,$user,$pass,$db) {

   $mysqli = new mysqli($host, $user, $pass, $db);

   if($mysqli->connect_error) 
     die('Connect Error (' . mysqli_connect_errno() . ') '. mysqli_connect_error());
return $mysqli; } 

for example

$mysqli = getConnected('localhost','user','password','database');