Stuck with a PHP index error - php

Question

just having an issue with an index error. It's basically throwing this at me
http://puu.sh/chc2e/7e26d51bda.png
I am unsure of why it's giving it to me as I have listed it in the index? Any ideas
My code:
<?php
include ('config.php');
?>
<?php
// Getting username and password from login form
$username = $_POST['username'];
$password = md5($_POST['password']);
// To protect MySQL injection
$username = stripslashes($username);
$password = stripslashes($password);
$username = mysql_real_escape_string($username);
$password = mysql_real_escape_string($password);
$sql="SELECT * FROM login WHERE username='$username' and password='$password'";
$result=mysql_query($sql);
// Mysql_num_row is to count number of row from the above query
$count=mysql_num_rows($result);
// count is 1 if the above username and password matches
if($count==1){
// now redirect to dashboard page, we also store the username in session for further use in dashboard
$_SESSION['username']= $username; // storing username in session
header("location:index.php");
}
//if the username and password doesn't match redirect to homepage with message=1
else {
echo '
<script language="javascript" type="text/javascript">
window.location.href="index.php?message=1";
</script>';
}
?>
Any help is appreciated. Thanks!
EDIT: User asked to see my Login form
<?php
if(isset($_POST["submit"])){
if(!empty($_POST['user']) && !empty($_POST['pass'])) {
$user=$_POST['user'];
$pass=$_POST['pass'];
$pass = strip_tags($pass);
$pass = md5($pass); // md5 is used to encrypt your password to make it more secure.
$con=mysql_connect('localhost','root','') or die(mysql_error());
mysql_select_db('aha') or die("cannot select DB");
$query=mysql_query("SELECT * FROM login WHERE username='".$user."' AND password='".$pass."'");
$numrows=mysql_num_rows($query);
if($numrows!=0)
{
while($row=mysql_fetch_assoc($query))
{
$dbusername=$row['username'];
$dbpassword=$row['password'];
}
if($user == $dbusername && $pass == $dbpassword)
{
session_start();
$_SESSION['sess_user']=$user;
/* Redirect browser */
header("Location: member.php");
}
} else {
echo "<div class='results'>Invalid username or password</div>";
}
} else {
echo "All fields are required!";
}
}
?>
HTML LOGIN:
<form action="" method="POST">
<label>Username:</label>
<input type="text" name="user" required />
<label>Password:</label>
<input type="password" name="pass" required />
<input type="submit" value="Login" name="submit" class="submit" />
<br><br>
<center>
<h2><p>Register</p></h2>
</center>

Answer 1

You have E_NOTICE enabled on your webserver (in php.ini).
You can typically ignore these errors, (disable them in your ini file will do the trick).
In order to fix the issue you need to define $username and $password as something (before the $_POST) because $_POST does not always exist.
$username = false;
$password = false;
for example.
As for the mysql issue, I strongly suggest looking into mysqli!
The standard mysql contains so many bugs, security issues and flaws it doesn't even exist anymore in the newer php versions.

Answer 2

in your first code change
$username = $_POST['user'];
$password = md5($_POST['pass']);
edit:
edit password line like point andrewsi

Answer 3

Change your login form with these name attributes :
<form action="" method="POST">
<label>Username:</label>
<input type="text" name="username" required />
<label>Password:</label>
<input type="password" name="password" required />
<input type="submit" value="Login" name="submit" class="submit" />
<br><br>
<center>
<h2><p>Register</p></h2>
</center>
</form>
Also replace all your $_POST['user'] and $_POST['pass'] occurences by $_POST['username'] and $_POST['password'] in your PHP code.

Answer 4

The fields are null, please var_dump() them. Need to see your frontend to determine more.
If you are posting form then try accessing the form via;
$_POST['Form']['Field']
Undefined Index means that the key you are trying to access in the array does not exist in the array. Undefined Index = Key (string), Undefined Offset = Index (number).