CSS 2 div size auto same height

Question

i have an question in CSS:

How i can do that:

When the green div has (auto)

Answer 1

Ideally you'd set a min-height on both cells, or as the answer by @Taeeril correctly suggest use javascript to equal out the heights.

Here is a solution using table display types http://jsfiddle.net/SebAshton/Pj7gy/