Check MySQL db connection in php

checkDbConnection.php

<?php

/**
 * Checking the MySQL connection
 */

 // Host name
 $host = "localhost";
 // MySQL username
 $username = "databaseusername";
 // MySQL password
 $password = "password";
 // MySQL database name
 $databasename = "dbname";

 echo "Checking connection with {$host}<br/>";

 // ------------------------------
 // Connect to mysql with the host, username, password
 // ------------------------------
 $con = mysql_connect($host,$username,$password);

 if (!$con)
 {
    die('Could not connect: ' . mysql_error());
 }

 // ------------------------------
 // Select database connection
 // ------------------------------
 $db_selected = mysql_select_db($databasename, $con);

 if (!$db_selected) die ("Can\'t use test_db : " . mysql_error());

 echo "Success!<br/>";

 // ------------------------------
 // Close connection
 // ------------------------------
 mysql_close($con);

?>