function getContentSize(gfxHoehe){
    var contentSize = document.getElementById("content").offsetHeight;
    var windowSize  = window.innerHeight - document.getElementById("header").offsetHeight - document.getElementById("footer").offsetHeight;
    if(contentSize < gfxHoehe){
        if(content < windowSize){
            document.getElementById("content").style.height = gfxHoehe+'px';
        }else{
            document.getElementById("content").style.height = windowSize+'px';
        }
	}
}