function off (name) {
  document[name].src='images/nav/'+name+'.gif';
}
function on (name) {
  document[name].src='images/nav/'+name+'_.gif';
}

function offPod (name) {
  document[name].src='images/pods/'+name+'.gif';
}
function onPod (name) {
  document[name].src='images/pods/'+name+'_.gif';
}

function offPage (name) {
  document[name].src='images/'+name+'.gif';
}
function onPage (name) {
  document[name].src='images/'+name+'_.gif';
}