//
//  (с) SiteLeader, 2005-2008 | http://www.siteleader.ru
//

var slider = null, limit = null, cur_ofs = 0, cur_delta = 0, delay = 15, timer, delta, step, i;
var l_btn, r_btn;

// подсветка кнопок
function _act(obj, value) {
  if (obj) {
    if (value) { if (obj.className != obj.id + '-a') obj.className = obj.id + '-a' }
    else if (obj.className != obj.id) obj.className = obj.id;
  }
}

function _do() {
  var dx = cur_ofs + i * (cur_delta += (step += delta)),
      minx = (window.sidebar) ? -slider.offsetWidth : -(slider.offsetWidth - limit.offsetWidth);
  // границы экрана
  if (dx > 0) {
    dx = 0; cur_ofs = 0; cur_delta = 0;
    clearInterval(timer);
    _act(l_btn, 0);
  } else if (dx < minx) { 
    dx = minx; cur_ofs = minx; cur_delta = 0;
    clearInterval(timer);
    _act(r_btn, 0);
  } else {
    _act(l_btn, 1);
    _act(r_btn, 1);
  }
  slider.style.marginLeft = dx + 'px';
  // стоп
  if (step < 0) {
    clearInterval(timer);
    cur_ofs += i * cur_delta;
    slider.style.marginLeft = cur_ofs + 'px';
    timer = (cur_delta = 0);
  }
}

// старт
function _go(obj) {
  step = 0;
  delta = 0.6;
  if (!obj || (!slider && !(slider = document.getElementById('slider')))) return;
  if (!limit && !(limit = document.getElementById('limit'))) return;
  if (timer) { clearInterval(timer); timer = 0; }
  i = obj.id.toLowerCase() == 'r-btn' ? -1 : (obj.id.toLowerCase() == 'l-btn' ? 1 : 0);
  timer = setInterval( function () { _do() }, delay );
  l_btn = document.getElementById('l-btn');
  r_btn = document.getElementById('r-btn');
}

// тормозим
function _slow(obj) { if (delta > 0) delta = -0.4 }