if (document.images) {
  homebuttonup       = new Image();
  homebuttonup.src   = "images/stuff/freeover.jpg" ;
  homebuttondown     = new Image() ;
  homebuttondown.src = "images/stuff/freeclick.jpg" ;
}

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" );
  }
}