How to make a popup open every 24 hours?

[thenetfreaker]

How to make a popup open every 24 hours depending on that the main page is open for a week ?

[clairec666]

Who in their right mind would keep the page open for a week? You could use a timeout, with time set to 1 week (1000x60x60x24 milliseconds!) or set the page so it refreshes every so often, and use an if statement to test if it is the right time to open the popup.