Delayed overlay popup script

I am not sure if this is possible ... but I would like to have a script made for webmasters that allows them to make an unblockable exit popup with yes / no buttons. Popup will ask if user would like to be automatically reminded online latter of whatever offer webmaster is offering. If user hits yes, the popup turns to a confirmation and user leaves site. latter, (time set by webmaster) generally 24hours later, while user is in web browser, a small overlay popup slides from an edge off the screen into view of user. This overlay popup is small and unobtrusive, and transparent, not covering the content user is currently viewing. This small sliding popup is a small reminder to the user and asks them if they would like to take action and contains a link that webmaster would take them back to if they click on it. The idea for this is that many internet buyers are interested in a product but don't buy on the first visit. This idea is to get the interested user back to a sales page without relying on them to read a followup email or click a bookmark. Please let me know if this is possible and if so, how you would implement such a script that internet marketer webmasters with not a lot of experience could set up. Thank you in advance.