滑动到当前位置，数字递增效果

html:

<div class="flexW">

　　<div class="num">350</div>

　　<div class="num">323435</div>

　　<div class="num">7</div>

　　<div class="num">25</div>

</div>

css:
.flexW{display:flex;justify-content: space-between;}
.num{width:23%;}

js:

$.fn.numChange = function(){
    var _this = this;
    $(window).scroll(function(){
        if($(window).scrollTop()>(_this.offset().top-$(window).height()-100)){
            if(!_this.attr('data-change')){
                _this.find('.num').each(function(){
                    let endNum = $(this).text()*100,
                        startNum = 0,
                        time = 100,
                        speed = 30,
                        addNum = Math.round(endNum/time),
                        _this = $(this);
                    _this.text(0);
                    var numChange = setInterval(function(){
                        startNum += addNum;
                        _this.text(Math.round(startNum/100));
                        if(startNum >= endNum){
                            clearInterval(numChange);
                        }
                    },speed)
                });
            }
            _this.attr('data-change','true');
        }
    });

}

$('.flexW').numChange();

$(window).trigger('scroll');