Interstitial Webpage
On the World Wide Web, interstitials are web pages displayed before or after an expected content page, often to display advertisements or confirm the user's age (prior to showing age-restricted material). Most interstitial advertisements are delivered by an ad server. Full-screen interstitial ads are referred to as hyperstitials.
Some people take issue with the use of such pages to present online advertising before allowing users to see the content they were trying to access. Less controversial uses of interstitial pages include introducing another page or site before directing the user to proceed; or alerting the user that the next page requires a login, or has some other requirement which the user should know about before proceeding.
Read more about Interstitial Webpage: Meaning of Interstitial, Circumvention