var SlideImages = [
                         'img/image1.jpg',
                         'img/image2.jpg',
                         'img/image3.jpg'

];
function switchImage (imgName, imgSrc){
  if (document.images) {
    if (imgSrc != "none") {
      document.images[imgName].src = imgSrc;
     }
  }
}
var SlideImages = new SlideShow (SlideImages, 'SlideImages', 6000, "SlideImages");
function SlideShow (slideList, image, speed, name){
  this.slideList = slideList;
  this.image = image;
  this.speed = speed;
  this.name = name;
  this.current = 0;
  this.timer = 0;
}

SlideShow.prototype.play = SlideShow_play;

function SlideShow_play (){
  with (this)
    {
      if (current++ == slideList.length-1) current = 0;
      switchImage (image, slideList[current]);
      clearTimeout (timer);
      timer = setTimeout(name+'.play()', speed);
    }
}