if(isset($_POST['url']) && $_POST['url'] == ''){

    $youremail = 'r10@eratalay.net.tr';  

    $name = isset($_POST['name']) ? $_POST['name'] : '';
    $number = isset($_POST['number']) ? $_POST['number'] : '';
    $email = isset($_POST['email']) ? $_POST['email'] : '';
    $subject = isset($_POST['subject']) ? $_POST['subject'] : '';
 
    $body = "You have got a new message from the quote form on your website :
     
    Name:  $name
    Phone Number:  $number
    Email:  $email
    Subject:  $subject";
 
    if( $email && !preg_match("/[\r\n]/", $email) ) {
      $headers = "From: $email";
    } else {
      $headers = "From: $youremail";
    }
 
    mail($youremail, 'Message from Web', $body, $headers );
 
}