function rollTab(name, over) {
  if(window.document.images) {
    if (over) window.document.images[name].src = "/images/nav/" + name + "_over.gif";
	else window.document.images[name].src = "/images/nav/" + name + "_off.gif";
  }
}

function rollButton(name, over) {
  if(window.document.images) {
    if (over) window.document.images[name].src = "/images/nav/" + name + "_over.gif";
	else window.document.images[name].src = "/images/nav/" + name + "_off.gif";
  }
}