How do you connect to multiple MySQL databases on a same webpage?

below i tell you ,How you connect to multiple MySQL databases on a same webpage?

$hostname='localhost';

$username='username';

$password='password';

$dbname='database1';

$hostname2='localhost';

$username2='username';

$password2='password';

$dbname2='database2';

$dbh1 = mysql_connect($hostname, $username, $password); 
$dbh2 = mysql_connect($hostname2, $username2, $password2); 

mysql_select_db('database1', $dbh1);
mysql_select_db('database2', $dbh2);

Then to query database 1, do

mysql_query('select * from tablename', $dbh1);

and for database 2

mysql_query('select * from tablename', $dbh2);