extracting text - regex

Hello, I am trying read text out of a text that is inbetween two divs. Somehow this should be possible with regex, I just can't figure out how. Example: <div id="test"> bla blub </div> I would like to extract the text "bla blub" out of this example. Has anybody an idea on how to do that? Is there a special php function available for this? Thank you for any hint, Merlin