// JavaScript Document

	var current_slide = 0;
	var next_slide_is = 'x';
	var transitioning = false;
	
	var transition_duration = 500;
	var slide_duration = 2500;
	
	var count_slides = 0;
	var loaded_slides = 0;
	
	var slide_interval = 0;



	// display a slide
	function select_slide(el) {
		// update "dots"
		for (var a = 1; a < 15; a++) {
			if (document.getElementById("dot_"+a)) { document.getElementById("dot_"+a).className = ''; }
		}
		document.getElementById("dot_"+el).className = 'selected';
	
		// fade in new photo
		if (current_slide !== el) {

			if (transitioning) {
				next_slide_is = el; 	// this chains the animation - if we're busy transitioning and a new slide is selected, complete the current transition first, then chain on this new animation
			} else {
				for (var a = 1; a < 15; a++) {
					if (document.getElementById("photo_"+a)) { document.getElementById("photo_"+a).style.zIndex = 1; }
				}
				if (document.getElementById("photo_"+current_slide)) { document.getElementById("photo_"+current_slide).style.zIndex = 2; }
				document.getElementById("photo_"+el).style.zIndex = 3;
				document.getElementById("photo_"+el).style.display = 'block';
				opacity("photo_"+el, 0, 100, transition_duration);
				transitioning = true;
				window.setTimeout("transition_reset()", transition_duration+10);
				current_slide = el;
			}
		} // current_slide !== el
		
		// new caption
		for (var a = 1; a < 15; a++) {
			if (document.getElementById("titles_"+a)) { document.getElementById("titles_"+a).style.display = "none"; }
		}
		document.getElementById("titles_"+el).style.display = "block";
	}
	
	
	// for chaining animation
	function transition_reset() {
		transitioning = false;
		if (next_slide_is !== 'x') {
			select_slide(next_slide_is);
			next_slide_is = 'x';
		}
	}
	
	
	// progress to next slide
	function next_slide() {
		next_slide_is = current_slide+1;
		if (next_slide_is > count_slides) { next_slide_is = 1; }
		select_slide(next_slide_is);
	}
	
	
	// user has manually selected a slide, make sure we reset interval timeout
	function change_slide(el) {	
		window.clearInterval(slide_interval);
		slide_interval = window.setInterval("next_slide()", slide_duration+transition_duration);
		select_slide(el);
	}