I use this to remember password
<?php
if($_POST['remember']) {
$remember_user = trim($_POST['username']);
$remember_pass = trim($_POST['password']);

$salt = "@g26jQsG&nh*&#8v";
$password_hash =  sha1($remember_pass.$salt);

setcookie('remember_user', $remember_user, $year);
setcookie('remember_pass', $password_hash, $year);


                $cookie_name = 'siteAuth';
        $cookie_time = time() - 100;
       $password_hash =  sha1($remember_pass.$salt);
   setcookie ($cookie_name, 'usr='.$remember_user.'&hash='.$password_hash, time() + $cookie_time);



}
else if(!$_POST['remember']) {
    if(isset($_COOKIE['remember_user']) && parse_str($_COOKIE['remember_pass'])) {

    if(($usr == $remember_user) && ($hash == md5($remember_pass)))
        {
        $_SESSION['username'] = $remember_user;
        }

                $cookie_name = 'siteAuth';
                $cookie_time = time() - 100;
                  setcookie ($cookie_name, 'usr='.$remember_user.'&hash='.$password_hash, time() + $cookie_time);

    }


}
?>

<input id="password" name="password" placeholder="Password" type="text" autocomplete="on" value="<?php
  $salt="@g26jQsG&nh*&#8v";
  $password = sha1($_COOKIE['remember_pass'].$salt); echo $password; ?>"/>