Faux columns is a web design technique that allows for the creation of the illusion of equal height columns using a background image in the body. This is seen as a CSS-based alternative to using HTML tables for column layout. The term was coined by Dan Cederholm in his article for A List Apart, Faux Columns. The application of faux columns has been extended through a method called liquid faux columns, which allows faux columns to adapt and re-proportion themselves to the browser height.
It’s a simple concept, but one that may alleviate one of the frustrations that designers frequently encounter when building CSS-based layouts.