gistfile1.php[345]

<?php
if(isset($_GET['username']) && $_GET['username']!="") {

    require_once("config.php");

    $username = $_GET['username'];

    if(!$handler = mysql_connect($host,$user,$pass)){
        throw new Exception(mysql_error($handler));
    }
 
    if(!mysql_select_db($db,$handler)){
        throw new Exception(mysql_error($handler));
    }

    $query = "SELECT * FROM $table WHERE username='".mysql_real_escape_string($username)."'";

    $results = mysql_query($query);

    if(mysql_num_rows($results) > 0) {
       echo"0";
    }else {
       echo"1";
    }
} 

if(isset($_GET['ajax'])) {

exit();

}

mysql_close($handler);
?>