Ok here is what I am trying to do. I am working with a number of ad agencies, and one agency pays great for 728x90 but their pay for 428x60 don't pay well, while another ad agency pays great for the smaller 428x60 but not so good on the 728x90. I would like to do this using responsive code, with each screen size calling a different html file via an iframe. So for a big display it would call the iframe html for 728x90 aka leaderboard.html For a smaller display it would call the iframe for 428x60 aka banner.html And for small devices (mobile) it would call the iframe for mobilead.html. I read all over including https://xenforo.com/community/threads/set-iframe-width-using-responsive-presets.56201/ but thats just for resizing the iframe based on screen size. I want to call a different iframe html source based on screen size. Can this be done? Thank you!