jQuery Novice to Ninja: Understanding math for crossfade slideshow

JavaScript
1

I’m having some difficulty understanding the math behind the crossfade slideshow on page 114.

If anyone can explain how this math works please let me know.

Thanks


$(document).ready(function(){
	rotatePics(0);
});

function rotatePics(currentPhoto) {
  var numberOfPhotos = $('#photos img').length;
  currentPhoto = currentPhoto % numberOfPhotos;
	
	$('#photos img').eq(currentPhoto).fadeOut(function() {
		// re-order the z-index
		$('#photos img').each(function(i) {
      		$(this).css(
        		'zIndex', ((numberOfPhotos - i) + currentPhoto) % numberOfPhotos
      		);
    	});

		$(this).show();
  		setTimeout(function() {rotatePics(++currentPhoto);}, 4000);
	});
}
2

Hey Jack, I haven’t done this yet but I think the concept is to stack the images then use the z-index in your css file to change which image is on top of the stack. It fades in every 4 seconds

(4000)

Is this what you mean. I’m a little confused as to what you are asking.