PHP undefined index error?

Question

I have a simple contact form thats throwing up an

"Notice: Undefined index: e in \nas43ent\Domains\m\mysite.co.uk\user\htdocs\contact-us.php on line 24"

error, I cant seem to see why however as my syntax looks correct?

<?php 

$name = $_POST['name'];
$email = $_POST['email'];
$subject = $_POST['subject'];
$message = $_POST['message'];
$to = "dave@.co.uk";

    //begin of HTML message
    $message = "
  From : $name,
  Email: $email,
  Subject: $subject,
  Message: $message ";
   //end of message

    // To send the HTML mail we need to set the Content-type header.
    $headers = "MIME-Version: 1.0\r\n";
    $headers .= "Content-type: text/html; charset=iso-8859-1\r\n";
    $headers  .= "From: Website Enquiry";


if (isset($_POST['name'])) {
       // now lets send the email.
   mail($to, $subject, $message, $headers);

header('Location: ' . $_SERVER['HTTP_REFERER'] . '?e=Thankyou, we will be in touch shortly.');

} else {header('Location: ' . $_SERVER['HTTP_REFERER'] . '?e=There was an error sending your message, Please try again.');}

?> 

Answer 1

Looks like it is related to e get parameter. After sending email you redirect user to some url like http://yourhost/com/somepage?e=Error+text

So the notice you get seems to be related to the place you display status message. You should put check there (as by default you don't have e in your query string):

if (isset($_GET['e'])) {
    //output message 
}

Answer 2

In place where you read $_GET['e'] paramter you should first check if it's present with isset:

if (isset($_GET['e'])) {
    // show the message to user
}

Answer 3

This is not an error but a NOTICE this is really different.

If $_SERVER['HTTP_REFERER'] is not set, you will receive this notice.

You should add if(isset($_SERVER['HTTP_REFERER'])).

Try the following

if (isset($_POST['name']) AND isset($_SERVER['HTTP_REFERER'])) {