function changeContent(year){
	var titleNode = document.getElementById("pub_title");
	var length = titleNode.childNodes.length;
	for  (var i = 0; i < length; i++){
		var node = titleNode.childNodes[i];
		if (node.nodeType  == "1"){
			if (node.id == year){
				node.style.display = "block";
			} else {
				node.style.display = "none";
			}
		}
	}
}