Develope a Pop-Under Script, which works for every browser and which is not blocked by most of the adblockers.

Hi there, we need a Popunder script which works for every browser and which is not blocked by most of the adblockers. We plan to work with the freelancer, who developes our script for longer, because it's common to update such scripts at least monthly due all of the browser updates. I am looking forward to your offers. Best Regards