m1 = new Image();
m1.src = "images/bt_sklep_off.gif";
m1_on = new Image();
m1_on.src = "images/bt_sklep_on.gif";

m2 = new Image();
m2.src = "images/bt_regulamin_off.gif";
m2_on = new Image();
m2_on.src = "images/bt_regulamin_on.gif";

m3 = new Image();
m3.src = "images/bt_o_firmie_off.gif";
m3_on = new Image();
m3_on.src = "images/bt_o_firmie_on.gif";

m4 = new Image();
m4.src = "images/bt_linki_off.gif";
m4_on = new Image();
m4_on.src = "images/bt_linki_on.gif";

m5 = new Image();
m5.src = "images/bt_kontakt_off.gif";
m5_on = new Image();
m5_on.src = "images/bt_kontakt_on.gif";


function img_over(obrazek) {
document[obrazek].src = eval(obrazek + "_on.src");
} 

function img_out(obrazek) {
document[obrazek].src = eval(obrazek + ".src");
} 

//Preload buttonów podmiany
function preload() {
  if (!document.images) return;
  var ar = new Array();
  var arguments = preload.arguments;
  for (var i = 0; i < arguments.length; i++) {
    ar[i] = new Image();
    ar[i].src = arguments[i];
  }
}