This trick will allow you to show AdSense Modal box to all links with the "showPromotion" class. Then after you click on Close button, you will go to the desired web pages.
To apply this trick, just add "showPromotion" class to the links you want to show Advertisement. Also remember to replace the given AdSense code with yours. Best regards.
Demo: https://tungpham42.github.io/adsense-trick/
About AdSense rules:
https://support.google.com/adsense/answer/1346295?hl=en#Placing_ads_in_pop-up_windows . You can be assured that the trick does not go against AdSense rules.
Publishers are not permitted to place Google ads in any window that is not initiated by an intentional user interaction (e.g., click). Additionally, Google ads may not be placed in any web browser window that lacks navigational controls, including back and forward browse buttons, and an editable URL field.
Publishers are not permitted to place Google ads on sites which have more than three pop-ups. If pop-ups are displayed on a site, they may not interfere with site navigation, change user preferences, initiate downloads, or distribute viruses.