var _current = 1;
var _total = 24;

function startSlideshow() {

	// Start timer
	window.setInterval("nextSlide()", 3000);
}

function nextSlide() {
	
	// Hide current
	hideSlide(_current);

	// Choose random slide
	//_current = Math.floor(Math.random()*24) + 1;
	
	// Next slide
	if (_current < _total) {
		_current = _current + 1;
	}
	else {
		_current = 1;
	}
	
	// Show new slide
	showSlide(_current);
}

function showSlide(slide_nr) {
	
	var slide = document.getElementById('slide_' + slide_nr);
	slide.style.display = 'block';
}

function hideSlide(slide_nr) {

	var slide = document.getElementById('slide_' + slide_nr);
	slide.style.display = 'none';
}