i have 4 divs inside of a div like this:

<div id="Wrapper">
    <div id="CoreSideBar"><!-- a sidebar to the right -->
    </div>
    <div id="SystemContent">
            <div id="SystemNavigation"><!-- will be some kind of "tabnavigation" in the top of this div -->
            </div>
        <div id="PageContent">
        </div>
        <div id="SystemSideBar"> <!-- a sidebar to the left -->
        </div>
    </div>
</div>

I would like the sidebars to have 200px width each and im also going to make it possible to "collapse" the sidebars so you can have more space for the PageContent div if you need it.

What do i need to do to make the PageContent div fill out the remaining whitespace between the CoreSideBar and the SystemSidebar? Is this even possible in all browsers?