PHP Database Connections with MySql

<?php
$con= mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$con) {
    die('Could not connect: ' . mysql_error());
}
mysql_select_db("mysql_database",$con);
echo 'Connected successfully';
mysql_close($con);
?>

localhost at different port like 3307,3308

<?php
$con= mysql_connect('localhost:3308', 'mysql_user', 'mysql_password');
if (!$con) {
    die('Could not connect: ' . mysql_error());
}
mysql_select_db("mysql_database",$con);
echo 'Connected successfully';
mysql_close($con);
?>

OR

<?php
$con= mysql_connect('127.0.0.1:3308', 'mysql_user', 'mysql_password');
if (!$con) {
    die('Could not connect: ' . mysql_error());
}
mysql_select_db("mysql_database",$con);
echo 'Connected successfully';
mysql_close($con);
?>