document.getElementById() alternative in jQuery

document.getElementById() alternative in jQuery

I have a flash floating banner. It has a X little button to stop floating, so the links from the other divs will be available. With this code down bellow I've managed to manipulate the overflow when clicking on the X button. It's working great, but from what I read document.getElementById works only with one ID and my idea now is to manipulate the floating banner with other blocks too. Let's say block2.
Is any solution with jQuery for that? Some example on jsfiddle will be really helpful.

  1. <script language="javascript">
  2. function doexpand() {
  3. document.getElementById("block1").style.overflow="visible";
  4. }
  5. function dolittle() {
  6. document.getElementById("block1").style.overflow="hidden" ;
  7. }
  8. </script>