In a method a web page hosting a tag script has a first area and a second area smaller than the first area. The first area contains a third area smaller than the first area. The third area is not positioned within the second area when the web page is loaded, and the third area contains a first ad content sourced from a first real-time ad bidding auction. Determining in real time via the tag script (a) whether the first ad content was loaded in the web page for a predefined time period, and (b) based on the other determining whether the third area has been scrolled into the second area as of or after the predefined time period has expired, and requesting a second real-time ad bidding auction for a second ad content to be input into the third area and replace the first ad content.