var plusImg = new Image();
plusImg.src = "http://www.progenicscryobank.com/_IMAGE/IMG_plus_0.jpg";
var minusImg = new Image();
minusImg.src = "http://www.progenicscryobank.com/_IMAGE/IMG_minus_0.jpg";

function hideLevel( _levelId, _imgId) { 
	var thisLevel = document.getElementById( _levelId );
	var thisImg = document.getElementById( _imgId);
	thisLevel.style.display = "none"; 
	thisImg.src = plusImg.src;
} 
function showLevel( _levelId, _imgId) { 
	var thisLevel = document.getElementById( _levelId ); 
	var thisImg = document.getElementById( _imgId);
	if ( thisLevel.style.display == "none") { 
		thisLevel.style.display = "block"; 
		thisImg.src = minusImg.src;
		}
		else { hideLevel( _levelId, _imgId);}
} 
function init() {
	hideAll();
};