function scroll(by){
	var by = by;
	window.scrollBy(0, by);
	if(document.getElementById("mitte_box_scroll") != null){
		hoehe_gesamt = document.getElementById("mitte_box_scroll").offsetHeight;
		minus = 240;
		nMinus = 460;
	}else{
		hoehe_gesamt = document.getElementById("navilistcontent").offsetHeight;
		minus = 340;
		nMinus = 460;
	}
	scroll_icon = document.getElementById("scrollicon");
	
	neu_max = hoehe_gesamt - nMinus;
	var neu = by + scroll_icon.offsetTop - minus;

	if(neu >= neu_max){
		neu = neu_max;
	}

	if(neu <= 75){
		neu = 75;
	}

	

//	alert(neu_max.toString() + " - " + hoehe_gesamt.toString());
	
//	alert(box_hoehe.toString());
//	alert(neu.toString() + " - " + hoehe_gesamt.toString());
	scroll_icon.style.top = neu + "px";
}