function showdiv(divnum, divbefor, navclass,conclass) {
	for (i = 1; i <= divnum; i++) {
		if (i == divbefor) {
			document.getElementById("Nav_" + i).className = navclass;
			document.getElementById("Content_" + i).className = conclass;
		} else {
			document.getElementById("Nav_" + i).className = "";
			document.getElementById("Content_" + i).className = "none";
		}
	}
}