$(init);

function init () {
	
	randomBanner("#topics .history a > img", ["/top/images/topics_history_a.jpg", "/top/images/topics_history_b.jpg"]);
}

function randomBanner (target, banners) {
	
	var random = Math.floor(Math.random() * banners.length);
	
	$(target).attr({src:banners[random]});
}