By default, Google Chrome blocks pop-ups from automatically showing up on your screen. When a pop-up is blocked, the address bar will be marked Pop-up blocked Pop-up blocked
. You can also decide to allow pop-ups.
If you still get pop-ups after disabling them, then you could have malware. Learn how to get rid of malware.
Firefox allows you to control both pop-ups and pop-unders in Firefox Options . Pop-up blocking is turned on by default, so you don't have to worry about enabling it to prevent pop-ups from appearing in Firefox.
When blocking a pop-up, Firefox displays an information bar (if it hasn’t been previously dismissed – see below), as well as an icon
in the address bar.