text: $().ready(function(){
      var index = takeMarginLeft(240);
      var margin_left = index[0];
      
      $('body').on('mouseenter', '#back-section-2', function(){
          hoverSmoke(margin_left, index[1]);
      }).on("mouseleave", "#back-section-2", function(){
          $('.smoke-slider').css('opacity','0');
      });
  
      $('.btn-slider-left').click(function(){
          if(margin_left < 0){
              $('.section-2-slider').css('margin-left', margin_left += 240);
          }
          hoverSmoke(margin_left, index[1]);
      });
      $('.btn-slider-right').click(function(){
          if(margin_left > -index[1]){
          $('.section-2-slider').css('margin-left', margin_left -= 240);
          }
          hoverSmoke(margin_left, index[1]);
      });
  });
  
  //function zone
  function takeMarginLeft(width_item){
      var margin_left =  $('.section-2-slider').css('margin-left');
      margin_left = parseInt(margin_left.split('px',1));
      var slider_width = $('.section-2-slider').css('width');
      slider_width = parseInt(slider_width.split('px',1));
      var items = Math.round(slider_width / width_item);
      var max_height = items - 5;
      var max_height = max_height * 240;
      
      return [margin_left, max_height];
  }
  function hoverSmoke(margin_left, index){
      if(margin_left == 0){
          $('.smoke-slider-right').css('opacity','1');
          $('.smoke-slider-left').css('opacity','0');
      }   else if( margin_left < 0 && margin_left > -index)   {
          $('.smoke-slider').css('opacity','1');
      }   else    {
          $('.smoke-slider-right').css('opacity','0');
          $('.smoke-slider-left').css('opacity','1');
      }
  }
  