User Login with Cookies

Creating the Login Form:

<form name="login" action="login.php" method="post">
  Username: <input type="text" name="username" size="30" maxlength="255" /><br/>
  Password: <input type="password" name="password" size="30" maxlength="255" /><br/>
  <input type="submit" value="Login" />
</form>

Creating the login.php file:
The login.php file will check to see that the username and password that have been entered into the form are valid. If they are, we will set a cookie with their information. This script assumes you are storing your passwords in the database using SHA1. Here is what login.php will look like:

<?php

  //include the database connection here...

  //convert username to uppercase... make it non-case sensitive.
  //then use the MD5 algorithm on the password
  $username = strtoupper($_POST['username']);
  $password = SHA1($_POST['password']);

  //query to run to database.  also converts username to uppercase.
  //counts how many times the username and password match (will either be 0 or 1)
  $query = "select * FROM users WHERE
      UPPER(username) = '$username' AND
      password = '$password'";

  $result = mysql_query($query);
  $count = mysql_num_rows($result);

  if ($count > 0)
  {
    //the username and password match.  we can now store the userid and password in the cookie.
    //we can use this for subsequent pages to figure out who the user is.
    $result = mysql_fetch_array($result);
    $userId = $result['userid'];

    //set the cookie
    setcookie("userId", $userId, time()+60*60*24*30);
    setcookie("userPass", $password, time()+60*60*24*30);

    //let them know they're logged in now.
    echo 'You are now logged in!';
  }
  else
  {
    //something wasn't right, so we can't log them in.
    echo 'Either your username or password were not correct.  Try again.';
  }
?>