how to detect blocked address from within php
<p>so here is my problem; we are trying to setup the facebook like and twitter tweet button on our website but it is causing browsers to become unresponsive when facebook and twitter are blocked on their computers.
so what i would like to do is detect if facebook or twitter are blocked and then remove the buttons for those computers, while allowing all others to load them.</p>

<p>is this possible in php or in javascript?</p>

<p>i haven't been able to locate any information about testing if a link is blocked or not.</p>
