Input Type Hidden

i need to track the source of a page which user browses ex: aboutus.html, contactus.html in which there is a link to enquiry.php where a user fills out a form. so i need to track which page the user originally came from(aboutus.html or contactus.html)

presently i am using enquiry.php to track the previous page with the following code

<input type='hidden' name='fromPage' value='<?php print $_REQUEST['fromPage']; ?>' />

i need to know what is the syntax in ASP for the above statement so that i can read the hidden value into a variable called source using Request.Form and later i can read this source variable in php