[Zope] Calling other frames

Hi there I have a navigation/sitemap object that shows the user where he is in the website at the current moment. I want this object eg. to sit in the left frame. This object must update every time the main (right) frame updates to reflect the position of the right frame. The website can be navigated both from this navigation/sitemap object or from links inside the website itself. Thus, the object must also update itself even if it is not used as the means to navigate the site. How do I "talk" to objects in other frames? Or is there a better way to do this? I know that this can probably be done with Javascript, but would prefer to use Zope as far as I can. Thanks! Etienne Tel: (012) 348 4586 Cel: 082 442 8981 Fax: (012) 361 8355