This is how to include a file from your root directory of your host provider. You will find this useful if you have files that you need to include from sub folders. <?php
$root = realpath($_SERVER["DOCUMENT_ROOT"]); include "$root/ExampleFolder/functions.php";
?> Change this /ExampleFolder/functions.php to the required destination of the file.
<div onclick="location.href='http://www.example.com';" style="cursor:pointer;"></div>
or for WordPress use this
<div id="header" onclick="location.href='<?php bloginfo('url');?>';" style="cursor:pointer;"></div>