function headerOver(elem,aelem) {
  elem.className='bgnavih';

  var el = document.getElementById(aelem);
  el.className = 'tahowht';

}

function headerOut(elem,aelem) {
  elem.className='bgnavi';

  var el = document.getElementById(aelem);
  el.className = 'tahored';

}

function headerOverFirst(elem,aelem) {
  elem.className='bgnavihfirst';

  var el = document.getElementById(aelem);
  el.className = 'tahowht';

}

function headerOverLast(elem,aelem) {
  elem.className='bgnavihlast';

  var el = document.getElementById(aelem);
  el.className = 'tahowht';

}