Push to Webpage
<p>How does Facebook and other pages seem to automatically push to webpages? They arent continually refreshing.</p>

<p>I know it would be through javascript but am a bit unsure on the theory. Is there a javascript script that is continuelly checking back with the facebook server to see if any updates are created?</p>

<p>Can someone point me into the right direction to where i can research how to add this functionality to my webpage? 
(Its probably more a javascript thing, however I am using C# ASP.NET)</p>
