var d = document;

var setup_events = function() {
	
	var dvs = d.getElementsByTagName('div'),
		dv,
		imgs,
		img,
		j,
		i = dvs.length;
	
	while (i--) {
		dv = dvs[i];
		if (dv.className.indexOf('speaker_work') == -1) continue;
		imgs = dv.getElementsByTagName('img');
		j = imgs.length;
		while (j--) {
			img = imgs[j];
			img.ind = j;
			img.onclick = function() {
				swap_className(this);
			};
		};
	};
	
};


var swap_className = function (img) {
	
	img.className = '';
	var p = img.parentNode,
		imgs = p.getElementsByTagName('img'),
		last_img = imgs[imgs.length - 1];
	if (img == last_img) {
		imgs[0].className = 'show';
	} else {
		imgs[img.ind+1].className = 'show';
	};
	
};

window.onload = function() {
	setup_events();
};