My problem is that i can seem to find a cross browser way to force the
content div to use 100% width when i set the menu div to
display:none;

I use left floating for the menu div and the content area right now.

design with menu
http://www.lojohnson.se/1.gif

design without menu
http://www.lojohnson.se/2.gif

I found a way doing this with a small JS script but there should be a
way to get it to work without it.

Please help!