不一样的radius

<script>
          $(document).ready(function(){
              $(window).scroll(function(){
                  var cur = $(window).scrollTop();
          //div position and next div position
                  var divs = $(".content > div");
                  $.each(divs, function(i, d){
                      //up position
                      //heights
                      var height =  0.4*$(d).height();
                      var curActiveTop = $(d).offset().top;
                      var nextActiveTop = $(d).next().offset().top;
                      if( cur+height > curActiveTop&&cur+height<nextActiveTop){
                          $(d).addClass("active").siblings().removeClass("active");
                      }
                  });
              });
          });
      </script>