var sectionBtn = null;

function navOver(ref) {
	if (sectionBtn!=ref) {
		var s = ref.src;
		var e = s.substring(s.length-5,s.length);
		e = e.replace("0","1");
		ref.src = s.substring(0,s.length-5)+e;
	}
}

function navOut(ref) {
	if (sectionBtn!=ref) {
		var s = ref.src;
		var e = s.substring(s.length-5,s.length);
		e = e.replace("1","0");
		ref.src = s.substring(0,s.length-5)+e;
	}
}

function setNav(ref) {
  var b = document.getElementById(ref);
  var s = b.src;
  var e = s.substring(s.length-5,s.length);
  e = e.replace("0","1");
  b.src = s.substring(0,s.length-5)+e;
  sectionBtn = b;
}