function DisplayNavLevel(vElementID,vLinkID) {
	var vElement = document.getElementById(vElementID);
	var vLink = document.getElementById(vLinkID);
	if (vElement.style.display == "none") {
	vElement.style.display = "block";
	vLink.innerHTML = "[-]";
	}
	else{
	vElement.style.display = "none";
	vLink.innerHTML = "[+]";
	}
	}