// JavaScript Document
var previousClass = '';
var previousEntered = '';
function enterTopNav(id){
	previousEntered = document.getElementById(id);
	previousClass = previousEntered.className;
	previousEntered.className = previousClass + " noBG";
	
}
function exitTopNav(){
	previousEntered.className = previousClass;
}
var previousContent = null;
function showContent(id){
	if(previousContent == null){
		previousContent = document.getElementById(firstContent);
	}		
	previousContent.style.display = 'none'; 	
	previousContent = document.getElementById(id);
	previousContent.style.display = 'block';
}