function toggleDiv(id){
	divElement = document.getElementById(id);
	
	if (divElement){
		if(divElement.className == 'invisible'){
			divElement.className = "visible";
		}else{
			divElement.className = "invisible";
		}
	}
}


enter= new Image();
enter.src = "images/welcome-nav-enter.jpg";
enteron = new Image();
enteron.src = "images/welcome-nav-enter-over.jpg";

entrez= new Image();
entrez.src = "images/welcome-nav-entrez.jpg";
entrezon = new Image();
entrezon.src = "images/welcome-nav-entrez-over.jpg";

/* standard image rollover functions */

function on(name){
	document[name].src = eval(name + "on.src");
}

function off(name){
	document[name].src = eval(name + ".src");
}