On a site I'm building, a user can edit certain fields on a node that cause a chain reaction to happen (which I've implemented using
hook_nodeapi's "update" op).
Since this chain reaction potentially affects a lot of other content, I'd like to inform the user of exactly what other content will be changed (which depends on the field values changed, which we don't know until the user submits the node). After the user has read this list of affected content, I'd like to give them the option to click "Yes" which will save the node and start the chain reaction, or click "No" which will take them back to the node edit form (with edits intact).
How can I make a confirmation form appear after the user clicks "Save"?