//alert("Tu som"); 
var Step = 1;
var Max;
var Foto;
function F_start(SM) {
   Max = SM;
   var ind = document.getElementById("Obraz").src.indexOf("_1.");
   var Prefix = document.getElementById("Obraz").src.slice(0, ind + 1);
   var Sirka = 100;
   var Vyska = 100;

   Foto = new Array(Max);
   for (i = 1; i <= Max; i++) {
      Foto[i] = F_Preload(Prefix + i + ".jpg");
      if (Sirka < Foto[i].width) Sirka = Foto[i].width;
      if (Vyska < Foto[i].height) Vyska = Foto[i].height;
   }
   document.getElementById("TaS").style.width = 8 + Sirka + "px";
   document.getElementById("TaS").style.height = 38 + Vyska + "px";
   document.getElementById("TaS").style.border = "1px solid #4682B4";
   document.getElementById("PoP").innerText = "1/" + Max;
}

function F_Preload(img) { var a = new Image(); a.src = img; return a; }
function F_vpred() { if (Step < Max) { Step += 1; F_zobraz(); } }
function F_spat() { if (Step > 1) { Step -= 1; F_zobraz(); } }

function F_zobraz() {
   document.getElementById("Obraz").src = Foto[Step].src;
   document.getElementById("PoP").innerText = Step + "/" + Max;
   if (Step == 1) { document.getElementById("LB").innerText = "Štart"; document.getElementById("RB").innerText = "Vpred"; }
   if (Step > 1 && Step < Max) { document.getElementById("LB").innerText = "Späť"; document.getElementById("RB").innerText = "Vpred"; }
   if (Step == Max) { document.getElementById("LB").innerText = "Späť"; document.getElementById("RB").innerText = "End"; }
}