// JavaScript Document

var max = 20;                   // This equals one more than the Array (below) because arrays start with zero.
var myImg= new Array(19)

  myImg[20]  = "sbj21";
  myImg[19]  = "sbj20";
  myImg[18]  = "sbj19";
  myImg[17]  = "sbj18";
  myImg[16]  = "sbj17";
  myImg[15]  = "sbj16";
  myImg[14]  = "sbj15";
  myImg[13]  = "sbj14";
  myImg[12]  = "sbj13";
  myImg[11]  = "sbj12";
  myImg[10]  = "sbj11";
  myImg[9]  = "sbj10";
  myImg[8]  = "sbj09";
  myImg[7]  = "sbj08";
  myImg[6]  = "sbj07";
  myImg[5]  = "sbj06";
  myImg[4]  = "sbj05";
  myImg[3]  = "sbj04";
  myImg[2]  = "sbj03";
  myImg[1]  = "sbj02";
  myImg[0]  = "sbj01";
                                 
myImgSrc = "sbj/";
myImgEnd = ".jpg"

var index_ptr = max;
var array_ptr = 0;

function loadImg()
{
  document.imgSrc.src = myImgSrc + myImg[index_ptr] + myImgEnd;
}

function prev()
{
  if(index_ptr == 0)
      {array_ptr = 0} 
  else 
      {array_ptr = index_ptr -=1};

  document.imgSrc.src = myImgSrc + myImg[array_ptr] + myImgEnd;
}

function next()
{
  if(index_ptr == max)
      {array_ptr = max} 
  else 
      {array_ptr = index_ptr +=1};

  document.imgSrc.src = myImgSrc + myImg[array_ptr] + myImgEnd;
}

function latest()
{
  if(index_ptr == max)
      {array_ptr = max} 
  else 
      {array_ptr = max};

  document.imgSrc.src = myImgSrc + myImg[array_ptr] + myImgEnd;
}


window.onload=loadImg;