Auto Scroll for chatbox??

I've tried to figure it out myself, but I cannot seem to get a CSS code to fix it. Before the chat changed, it would auto keep scrolled down to where the newest post was. Now, it stays in the place you last posted. One of my members even said that when he posts it will shoot back up to the middle of the chat. I'd like to find a code that will make it stay where ever the newest posts are.

Can someone help me?

Thanks.