Self-validating referer feature not working any more?

I used to use this HTML to create a button to check the page it
is on.  This seems to no longer work:

<a href="http://validator.w3.org/check/referer">
<img border="0" src="http://www.w3.org/Icons/valid-html40"
alt="[We test our html]" height="31" width="88" align=right></a>

Is there an alternative way to do this?

				-BN