function fotos_openen(){
    new Effect.Fade('product_overzicht', {duration: 0.0, delay: 0.0}) ;
	new Effect.Appear('extra_fotos', {duration: 0.0, delay: 0.0}) ;
}

function overzicht_openen(){
    new Effect.Fade('extra_fotos', {duration: 0.0, delay: 0.0}) ;
	new Effect.Appear('product_overzicht', {duration: 0.0, delay: 0.0}) ;
}