function selectCN(t,s)
{
  t.onmouseout = null;
  t.onmouseover = null;
  t.onclick = function onclick() { deselectCN(this,s); };
}
function deselectCN(t,s)
{
  t.onmouseout = function onmouseout() { dropCN(this); };
  t.onmouseover = function onmouseover() { highlightCN(this,'#FFF000'); };
  t.onclick = function onclick() { selectCN(this,s); };
}