var photo = new Array();
var photoNum = 0;

photo[0] ="images/label-1.gif";
photo[1] ="images/label-2.gif";
photo[2] ="images/label-3.gif";
photo[3] ="images/label-4.gif";
photo[4] ="images/label-5.gif";
photo[5] ="images/label-6.gif";
photo[6] ="images/label-7.gif";
photo[7] ="images/label-8.gif";

var collPhoto = new Array();

collPhoto[0] = "images/collCat2010-1.jpg";
collPhoto[1] = "images/collCat2010-2.jpg";
collPhoto[2] = "images/collCat2010-3.jpg";
collPhoto[3] = "images/collCat2010-4.jpg";
collPhoto[4] = "images/collCat2010-5.jpg";
collPhoto[5] = "images/collCat2010-6.jpg";
collPhoto[6] = "images/collCat2010-7.jpg";
collPhoto[7] = "images/collCat2010-8.jpg";
collPhoto[8] = "images/collCat2010-9.jpg";
collPhoto[9] = "images/collCat2010-10.jpg";
collPhoto[10] = "images/collCat2010-11.jpg";
collPhoto[11] = "images/collCat2010-12.jpg";
collPhoto[12] = "images/collCat2010-13.jpg";
collPhoto[13] = "images/collCat2010-14.jpg";
collPhoto[14] = "images/collCat2010-15.jpg";
collPhoto[15] = "images/collCat2010-16.jpg";
collPhoto[16] = "images/collCat2010-17.jpg";
collPhoto[17] = "images/collCat2010-18.jpg";
collPhoto[18] = "images/collCat2010-19.jpg";
collPhoto[19] = "images/collCat2010-20.jpg";
collPhoto[20] = "images/collCat2010-21.jpg";
collPhoto[21] = "images/collCat2010-22.jpg";


function forward(nameArray, nameImages) {
  if (photoNum < nameArray.length - 1) {
    photoNum = photoNum + 1;
    document.getElementById(nameImages).src = nameArray[photoNum];
  }
  else {
    photoNum = 0;
    document.getElementById(nameImages).src = nameArray[photoNum];
  }
  imageNum(nameArray);
}

function backward(nameArray, nameImages) {
  if (photoNum > 0) {
    photoNum = photoNum - 1;
    document.getElementById(nameImages).src = nameArray[photoNum];
  }
  else {
    photoNum = nameArray.length - 1;
    document.getElementById(nameImages).src = nameArray[photoNum];
  }
  imageNum(nameArray);
}

function imageNum(nameArray) {
  var imagediv = document.getElementById("position-string");
  imagediv.innerHTML = (photoNum + 1) + " of " + nameArray.length;
}