function toggleAbstract(id) {
	var divs = document.getElementsByTagName("span");
	for ( var pos = 0; pos < divs.length; ++pos) {
		var div = divs.item(pos);
		if (div.className == "abstract open")
			div.className = "abstract closed";
		else if (div.className == "abstract closed" && div.id == id) {
			div.className = "abstract open";
			div.parentNode.scrollIntoView(false);
		}
	}
}