function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    };
  }
};

function doSlideshow() {
	slidenum = 0;
	for(i=0; i<images.length; i++) {
		var preload = new Image();
		preload.src = images[i];
	}
}

function previousSlide() {
	slidenum--;
	if(slidenum<0) {slidenum = images.length-1;}
	var newslide = document.getElementById('slide');
	newslide.src = images[slidenum];
	newslide.setAttribute("title", captions[slidenum]);
	document.getElementById('currentslide').innerHTML = slidenum+1;
	document.getElementById('slidecaption').innerHTML = captions[slidenum];
}

function nextSlide() {
	slidenum++;
	if(slidenum>=images.length) {slidenum = 0;}
	var newslide = document.getElementById('slide');
	newslide.src = images[slidenum];
	newslide.setAttribute("title", captions[slidenum]);
	document.getElementById('currentslide').innerHTML = slidenum+1;
	document.getElementById('slidecaption').innerHTML = captions[slidenum];
}