A banner ad is a particular kind of online advertising resource that often shows up at the top or side of a webpage. It is an HTML construct that displays a given advertisement and, when clicked, takes the user to the advertiser's site.
The standard banner ad sizes across the internet are: 720×90, 300×600, 300×250.
Banner ads have been popular throughout most of the internet era. Banner ads developed relatively early as a major part of online advertising. Banner ad markets involve websites offering specific prices and rates for banner ad placement.
The Internet Advertising Bureau has specified various pixel sizes for banner ads. Unlike some other kinds of ads, banner ads can also contain video or rich media. In general, the banner ad is a sort of "legacy internet fixture" that is familiar to early users of the internet, and is now being eclipsed by other more sophisticated types of online ads.