PHP - sending email with attachment does not show message content -

trying create script can send email attachments. works except when don't add file in email can still see attachment 0b , no name.

if(isset($_post["my_send"])){       $email_to = $_post['my_email_to']; //required      $email_from = "myemail@example.co.uk"; // required      $subject = $_post['my_subject']; // not required      $comments = $_post['write_my_email']; // required      $email_message .= stripcslashes("$comments");      $attachment = chunk_split(base64_encode(file_get_contents($_files['file']['tmp_name'])));     $filename = $_files['file']['name'];  // create email headers  $headers = 'from: '.$email_from."\r\n". $headers .= "mime-version: 1.0\r\n"; $headers .= "content-type: multipart/mixed; boundary=\"_1_$boundary\"\r\n";  'reply-to: '.$email_from."\r\n" .  'x-mailer: php/' . phpversion();  $message="this multi-part message in mime format.  --_1_$boundary content-type: multipart/alternative; boundary=\"_2_$boundary\"  --_2_$boundary content-type: text/plain; charset=\"iso-8859-1\" content-transfer-encoding: 7bit  $email_message  --_2_$boundary-- --_1_$boundary content-type: application/octet-stream; name=\"$filename\"  content-transfer-encoding: base64  content-disposition: attachment   $attachment --_1_$boundary--";   mail($email_to, $subject, $message, $headers);             echo "<h5>thanks, email sent successfully!</h5>";  } 

what doing wrong? advice?

just exclude when there no attachment:

--_1_$boundary content-type: application/octet-stream; name=\"$filename\"  content-transfer-encoding: base64  content-disposition: attachment   $attachment --_1_$boundary-- 

for example, appending $message when filename not empty:

$message = "this multi-part message in mime format.     --_1_$boundary     content-type: multipart/alternative; boundary=\"_2_$boundary\"      --_2_$boundary     content-type: text/plain; charset=\"iso-8859-1\"     content-transfer-encoding: 7bit      $email_message";  if (!empty($filename)) {    $message .= " --_1_$boundary         content-type: application/octet-stream; name=\"$filename\"          content-transfer-encoding: base64          content-disposition: attachment           $attachment         --_1_$boundary--"; }