var photo = new Array()
var photoNum = 0

photo[0] ="images/federal-schematic/1.jpg"
photo[1] ="images/federal-schematic/2.jpg"
photo[2] ="images/federal-schematic/3.jpg"
photo[3] ="images/federal-schematic/4.jpg"
photo[4] ="images/federal-schematic/5.jpg"
photo[5] ="images/federal-schematic/6.jpg"
photo[6] ="images/federal-schematic/7.jpg"
photo[7] ="images/federal-schematic/8.jpg"
photo[8] ="images/federal-schematic/9.jpg"
photo[9] ="images/federal-schematic/10.jpg"
photo[10] ="images/federal-schematic/11.jpg"
photo[11] ="images/federal-schematic/12.jpg"
photo[12] ="images/federal-schematic/13.jpg"
photo[13] ="images/federal-schematic/14.jpg"
photo[14] ="images/federal-schematic/15.jpg"
photo[15] ="images/federal-schematic/16.jpg"
photo[16] ="images/federal-schematic/17.jpg"
photo[17] ="images/federal-schematic/18.jpg"
photo[18] ="images/federal-schematic/19.jpg"
photo[19] ="images/federal-schematic/20.jpg"
photo[20] ="images/federal-schematic/21.jpg"
photo[21] ="images/federal-schematic/22.jpg"
photo[22] ="images/federal-schematic/23.jpg"
photo[23] ="images/federal-schematic/24.jpg"
photo[24] ="images/federal-schematic/25.jpg"
photo[25] ="images/federal-schematic/26.jpg"
photo[26] ="images/federal-schematic/27.jpg"
photo[27] ="images/federal-schematic/28.jpg"
photo[28] ="images/federal-schematic/29.jpg"

function forward() {
  if (photoNum < photo.length - 1) {
    photoNum = photoNum + 1;
    document.images.gallery.src=photo[photoNum];
  }
  else {
    photoNum = 0;
    document.images.gallery.src=photo[photoNum];
  }
  imageNum();
}

function backward() {
  if (photoNum > 0) {
    photoNum = photoNum - 1;
    document.images.gallery.src=photo[photoNum];
  }
  else {
    photoNum = photo.length - 1;
    document.images.gallery.src=photo[photoNum];
  }
  imageNum();
}

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