if (document.images) {
    homebuttonup       = new Image();
    homebuttonup.src   = "tabs/home-off.gif" ;
    homebuttondown     = new Image() ;
    homebuttondown.src = "tabs/home-on.gif" ;

    aboutbuttonup       = new Image();
    aboutbuttonup.src   = "tabs/faq-off.gif" ;
    aboutbuttondown     = new Image() ;
    aboutbuttondown.src = "tabs/faq-on.gif" ;
    
    servicesbuttonup       = new Image();
    servicesbuttonup.src   = "tabs/services-off.gif" ;
    servicesbuttondown     = new Image() ;
    servicesbuttondown.src = "tabs/services-on.gif" ;
    
    startingbuttonup       = new Image();
    startingbuttonup.src   = "tabs/starting-off.gif" ;
    startingbuttondown     = new Image() ;
    startingbuttondown.src = "tabs/starting-on.gif" ;
    
    busservicesbuttonup       = new Image();
    busservicesbuttonup.src   = "tabs/bus-services-off.gif" ;
    busservicesbuttondown     = new Image() ;
    busservicesbuttondown.src = "tabs/bus-services-on.gif" ;
}
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" );
    }
}