$(document).on('mousewheel DOMMouseScroll', function(event) {
        event.preventDefault();
        if(delay) return;

        delay = true;
        setTimeout(function(){delay = false},200)

        var wd = event.originalEvent.wheelDelta || -event.originalEvent.detail;

        var a= document.getElementsByTagName('div');
        if(wd < 0) {
          for(var i = 0 ; i < a.length ; i++) {
            var t = a[i].getClientRects()[0].top;
            if(t >= 40) break;
          }
        }
        else {
          for(var i = a.length-1 ; i >= 0 ; i--) {
            var t = a[i].getClientRects()[0].top;
            if(t < -20) break;
          }
        }
        $('html,body').animate({
          scrollTop: a[i].offsetTop
        });
      });
    })();