function roll_over( name ) {
  if( document.images ) {
    if( document [name].src.indexOf( '_on' ) == -1 )
      document [name].src = eval( name + "_on.src" )
    else
      document [name].src = eval( name + "_off.src" )
  }
}

if (document.images) {
about_on = new Image()
about_on.src = "images/nav_about_on.gif"

about_off = new Image()
about_off.src = "images/nav_about_off.gif"

amenities_on = new Image()
amenities_on.src = "images/nav_amenities_on.gif"

amenities_off = new Image()
amenities_off.src = "images/nav_amenities_off.gif"

tour_on = new Image()
tour_on.src = "images/nav_tour_on.gif"

tour_off = new Image()
tour_off.src = "images/nav_tour_off.gif"

reservations_on = new Image()
reservations_on.src = "images/nav_reservations_on.gif"

reservations_off = new Image()
reservations_off.src = "images/nav_reservations_off.gif"
}