Equal height columns on a responsive/flexible layout

I’m trying to achieve equal height columns on a ‘responsive’ website.

That means I’m using media queries to provide several layouts for one website.

I have 2 columns which need to have the same height. It’s easy to achieve when the layout is fixed. I found dozens of scripts that do it and it works well.

However when I resize the browser window, that generated height doesn’t change. So if the window is smaller, the height of the columns stays the same as before and the contents of the columns overflows. It’s ugly.

Is there a way that generated height could change as I resize the window ?

Note : because of what’s inside the columns I cannot use any CSS trick with backgrounds images etc. I really REALLY need both columns to truly have the same height at all times.

Thanks in advance