if($_POST['markasread']) {

#grab users details from db

$usersemailaddress = $_SESSION['email'];
$grabusersinformation = mysql_query("SELECT id, email, username FROM people WHERE email = '$usersemailaddress'") or die("Error Grabbing User's Information");
$iduser = mysql_fetch_assoc($grabusersinformation);
$time = time();

$markasread = mysql_query("UPDATE `people` SET `lastchecked` = '$time' WHERE user_id = '$iduser[id]'") or die("There was a problem marking your Mentions as read");

header('Location: '.$_SERVER['HTTP_REFERER']);