I finished a Wordpress-based website for a client several months ago and I received an upgrade request just recently. They create and maintain their own content, but they also have a few links for external vendor deals. These vendors are fixed and the links are imbedded in a static sidebar. The client would like to inform users they're leaving the client's website when these vendor links are clicked with a simple "Yes or No" prompt. What's a good solution for achieving this? Thanks! P.S. I don't like it, but they insist they're required to inform users of where they're going (even if they should be able to figure it out).