function toggleNav(elem){
	if(elem == 'product' || elem == 'references'){
		if(document.getElementById("nav_"+elem).style.display == "block")
			document.getElementById("nav_"+elem).style.display = "none";
		else{
			document.getElementById("nav_"+elem).style.display = "block";
			elem1 = (elem == "product")?"references":"product";
			document.getElementById("nav_"+elem1).style.display = "none";
		}
	}
	else{
		document.getElementById("nav_product").style.display = "none";
		document.getElementById("nav_references").style.display = "none";
	}
	//alert(document.getElementById("nav_"+elem).className);
}