I currently have two columns, with another column in-between them. What I want is to have the left and right columns extend in height as the centre column has more content a
Extending div to correct height, or lets say 100% height of the container, You have to chain height:100% up to the container with fixed height or to the body with another height: 100%;. On the long run, you will probably require this solution.
Since there is no fixed height, I used height: 100% and chained up to the body an html.
body, html { height: 100%; }
.flight
{
float: right;
border: 1px solid green;
height: 100%;
}
Demo
TO give exact height of container to the sidebars, you either have to use fixed height or use javascript.