A dynamic "future" date stamp

Hello folks,

I am looking to insert a future date automatically in a dynamic stamp. That is, I would like to be able to have the stamp automatically add X days to the current date. I have seen a lot of JavaScript forums, tried many of the proposed solutions, but have yet to find something that works for my dynamic stamp. Currently my stamp looks like this:

event.value = (new Date()).toString();
AFDate_FormatEx("mmmm d, yyyy");

Amy help would be greatly appreciated. Thanks!