make a div stick with the higher one

Hi,

under Joomla, i have 5 divs.
- 1 on the top for main menu and banners
- 1 on the left for my menu category,
- 1 central for the content
- 1 on the right for ads.
- and 1 as footer

as my content div heigh changes during the web browsing, i would like to make my left div (category menu) still reaching my footer div.
this is needed because my left div as for background-color a different color than the content one.

how can i do to make the left div everytime reaching the footer one even if my content div heigh is changing ?

thanks a lot,
A.

 

Can you post your site url here?

 

sorry but for now it is on my localhost development computer. i still didn't store it on internet till now as i'm working on it.

 

try margin:auto

or

height:9999px;
background-position:top;
overflow:hidden;