if (document.images) {
    directbuttonup       = new Image();
    directbuttonup.src   = "images/direct.png" ;
    directbuttondown     = new Image() ;
    directbuttondown.src = "images/direct-1.png" ;
    reservationsbuttonup       = new Image();
    reservationsbuttonup.src   = "images/reservations.png" ;
    reservationsbuttondown     = new Image() ;
    reservationsbuttondown.src = "images/reservations-1.png" ;
}
function buttondown( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "down.src" );
    }
}
function buttonup ( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "up.src" );
    }
}