This article explains how to disable the pop-up blocker on iPhone and iPad using Safari. Instructions apply to most versions of iOS.
Allow pop-ups in Safari on iPhone or iPad
Safari’s built-in pop-up blocker is a welcome feature in iOS. By default, your iOS devices prevent web pages from opening pop-ups, but you can disable the pop-up blocker on iPhone and iPad with just a few taps.
Unfortunately, you can't specify a list of approved websites for which Safari can disable the pop-up blocker on an as-needed basis; it's an all-or-nothing proposition, with the pop-up blocker either all the way on or all the way off. So if you want to see a pop-up for a specific website, turn the pop-up blocker off, then turn it back on later.
Go to Settings > Safari.
