var slide = {

  current_id: 1,

  max_id: 0,

  next: function() {
    var next_id = slide.current_id + 1;
    if (YAHOO.util.Dom.get('slide_'+next_id))
      slide.select(next_id);
    else
      slide.select(1);
  },

  previous: function() {
    var next_id = slide.current_id - 1;
    if (YAHOO.util.Dom.get('slide_'+next_id))
      slide.select(next_id);
  },

  set_title: function(next_slide) {
    var title = YAHOO.util.Dom.getFirstChild(next_slide).title;
    var caption_container = YAHOO.util.Dom.get('slide_caption');
    caption_container.innerHTML = title;
  },

  select: function(next_id) {
    var next_slide = YAHOO.util.Dom.get('slide_'+next_id);
    if (next_slide) {
      var previous_slide = YAHOO.util.Dom.get('slide_'+slide.current_id);
      var next_nav = YAHOO.util.Dom.get('slide_nav_'+next_id);
      var previous_nav = YAHOO.util.Dom.get('slide_nav_'+slide.current_id);
      slide.current_id = next_id;
      if (previous_slide)
        YAHOO.util.Dom.removeClass(previous_slide,'active');
      if (previous_nav)
        YAHOO.util.Dom.removeClass(previous_nav,'active');
      if (next_nav)
        YAHOO.util.Dom.addClass(next_nav,'active');
      YAHOO.util.Dom.addClass(next_slide,'active');
      slide.set_title(next_slide);
    }
  }
}