var ImgNum = 0;
var ImgLength = NewImg.length - 1;


function chgImg(direction) {
if (document.images) {
ImgNum = ImgNum + direction;
if (ImgNum > ImgLength) {
ImgNum = 0;
}
if (ImgNum < 0) {
ImgNum = ImgLength;
}
document.slideshow.src = NewImg[ImgNum];
document.getElementById("captionarea").innerHTML  = Captions[ImgNum];

   }
}