function exchange(obj1, obj2) {
		document.getElementById(obj1).style.display = "block";
		document.getElementById(obj2).style.display = "none";
		document.getElementById(obj1+"-link").style.display = "block";
		document.getElementById(obj2+"-link").style.display = "none";
		document.getElementById(obj1+"-tab").className = "visible";
		document.getElementById(obj2+"-tab").className = "hidden";
	}