if (document.images) {
    servicebuttonup       = new Image();
    servicebuttonup.src   =   "grafx/menu-buttons/Services.jpg" ;
    servicebuttondown     = new Image() ;
    servicebuttondown.src = "grafx/menu-buttons/Services_on.jpg" ;

    teambuttonup       = new Image();
    teambuttonup.src   =   "grafx/menu-buttons/OurTeam.gif" ;
    teambuttondown     = new Image() ;
    teambuttondown.src = "grafx/menu-buttons/OurTeam_on.gif" ;

    officebuttonup       = new Image();
    officebuttonup.src   =   "grafx/menu-buttons/OurOffice.gif" ;
    officebuttondown     = new Image() ;
    officebuttondown.src = "grafx/menu-buttons/OurOffice_on.gif" ;

    artisticbuttonup       = new Image();
    artisticbuttonup.src   =   "grafx/menu-buttons/ArtisticDentistry.gif" ;
    artisticbuttondown     = new Image() ;
    artisticbuttondown.src = "grafx/menu-buttons/ArtisticDentistry_on.gif" 

    contactbuttonup       = new Image();
    contactbuttonup.src   =   "grafx/menu-buttons/ContactUs.gif" ;
    contactbuttondown     = new Image() ;
    contactbuttondown.src = "grafx/menu-buttons/ContactUs_on.gif" 
}

function img_over( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "down.src" );
    }
}

function buttonup ( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "up.src" );
    }
}