Archived - iPhone: Managing Pop-Ups in Safari
Many websites have pop-ups — new pages that appear when you didn't intend for them to. Often, pop-ups are advertisements.
To Block or Allow Pop-Ups
From the Home screen choose Settings > Safari, then turn Block Pop-ups on or off.
Blocking pop-ups stops only pop-ups that appear when you close a page or open a page by typing its address. It doesn't block pop-ups that open when you click a link.