// Window höhe ermitteln, für IE und FF getestet
function getWindowHeight(win)
{
    if (win == undefined)
        win = window;
    if (win.innerHeight) {
        return win.innerHeight;
    } else {
        if (win.document.documentElement 
                && win.document.documentElement.clientHeight) 
        {
            return win.document.documentElement.clientHeight;
        }
        return win.document.body.offsetHeight;
    }
}