Want to use a scroll-tag more than one time, is it possible?

Hi, thanks for reading this!! :-)

I got the problem, that I programmed a chat. My second edition gets all the data out of a database, so you do not have to refresh every 5 seconds, but I want the browser to scroll to the end every time a new entry is given.
I tried it with scrollBy, scrollTo and scroll, but nothing worked the way I wanted it. The first time in a document the tag does it job, but the second time nothing happens.
I would be glad to hear from you.
(in english or in german) Thanks!

Please do not mind my english!