<?php
// config
include("../config.php");

mysql_connect($host, $user, $pass) or die(mysql_error());
mysql_select_db($database) or die(mysql_error());

$query = 'SELECT email FROM recipients where email =' . intval($_POST['number']);
$result = mysql_query($query) or die(mysql_error());
if(mysql_num_rows($result) > 0) {
//username already exists
echo "yes";
}
else{
echo "no";
}

?>