function next_slide() {
  current_slide = current_slide + 1;
  
  if (current_slide == 3) {
    click_pause();
  } 
  
  if (current_slide >= 4) {
    current_slide = 0;
    $('scroller').setStyle({left:'0px'});
  }
  
  scroll_slide(current_slide);

  if (auto_play == true) {
    ctime = setTimeout("next_slide();", 7000);
  } 
}

function click_next_slide() {
  auto_play = false;
  $('pause_button').className = "pngfix play";
  clearTimeout(ctime);
  next_slide();
}

function click_pause() {
  if (auto_play == true) {
    auto_play = false;
    $('pause_button').className = "pngfix play";
    clearTimeout(ctime);
  } else {
    auto_play = true;
    $('pause_button').className = "pngfix pause";
    next_slide();
  }
}

function scroll_slide(slide){
  new Effect.Move('scroller', {x:-slide*990,y:0,mode:'absolute'});
}