var scroll_teller = 0;
var scroll_px = 0;
var scroll_timer;
			
function ScrollOmhoog() {
	clearTimeout(scroll_timer);
	if (scroll_teller < 7) {
		scroll_teller = scroll_teller + 1;
		scroll_px = scroll_px+(-0.25*Math.pow(scroll_teller,2)+2*scroll_teller-0.75);
		document.getElementById("propcontent").style.marginTop = "-"+Math.round(scroll_px)+"px";
		scroll_timer = setTimeout("ScrollOmhoog("+scroll_px+");",70);
	}
}
function ScrollOmlaag() {
	clearTimeout(scroll_timer);
	if (scroll_teller > 0) {
		scroll_px = scroll_px-(-0.25*Math.pow(scroll_teller,2)+2*scroll_teller-0.75);
		scroll_teller = scroll_teller - 1;
		document.getElementById("propcontent").style.marginTop = "-"+Math.round(scroll_px)+"px";
		scroll_timer = setTimeout("ScrollOmlaag("+scroll_px+");",70);
	}
}