b1_on= new Image;
b1_off=new Image;
b1_on.src= "img/mapa_on.gif";
b1_off.src= "img/mapa.gif";

b2_on= new Image;
b2_off=new Image;
b2_on.src= "img/kontakt_on.gif";
b2_off.src= "img/kontakt.gif";

b3_on= new Image;
b3_off=new Image;
b3_on.src= "img/gora_on.gif";
b3_off.src= "img/gora.gif";