Detect if user is a first time visitor, if so, re-direct to page, if not, re-direct to another page

Question

Is there a way to detect if a user is visiting my website for the first time, and if so, redirect them to a page, for example, index-first-time-visitor.php - and if they are not a first time visitor, it sends them to index.php

If there is a way to do this, please demonstrate how.

Answer 1

Put this at the top of your index.php

<?php
if ($_COOKIE['iwashere'] != "yes") { 
  setcookie("iwashere", "yes", time()+315360000);  
  header("Location: http://example.com/index-first-time-visitor.php"); 
}
?>

The cookie will live for 10 years, after that, a user will be a "new" visitor again.