JS控制数字从指定数开始变化

// 引用基本的jquery.js
<!-- 数字变化 -->
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    <div class="content f-cb">
        <div>
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        </div>
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        </div>
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</div>
<script type="text/javascript">
var istrue = true;
$(window).on("scroll",
  function() {
    var s = $(window).scrollTop();
    $(".timer").each(count);
    function count(a) {
        var b = $(this);
        a = $.extend({},
        a || {},
        b.data("countToOptions") || {});
        b.countTo(a)
    };
    istrue = false;
    $(".timer").removeClass("timer")
})
//设置计数
$.fn.countTo = function (options) {
    options = options || {};
    return $(this).each(function () {
        //当前元素的选项
        var settings = $.extend({}, $.fn.countTo.defaults, {
            from:            $(this).data('from'),
            to:              $(this).data('to'),
            speed:           $(this).data('speed'),
            refreshInterval: $(this).data('refresh-interval'),
            decimals:        $(this).data('decimals')
        }, options);
        //更新值
        var loops = Math.ceil(settings.speed / settings.refreshInterval),
            increment = (settings.to - settings.from) / loops;
        //更改应用和变量
        var self = this,
        $self = $(this),
        loopCount = 0,
        value = settings.from,
        data = $self.data('countTo') || {};
        $self.data('countTo', data);
        //如果有间断，找到并清除
        if (data.interval) {
            clearInterval(data.interval);
        };
        data.interval = setInterval(updateTimer, settings.refreshInterval);
        //初始化起始值
        render(value);
        function updateTimer() {
            value += increment;
            loopCount++;
            render(value);
            if (typeof(settings.onUpdate) == 'function') {
                settings.onUpdate.call(self, value);
            }
            if (loopCount >= loops) {
                //移出间隔
                $self.removeData('countTo');
                clearInterval(data.interval);
                value = settings.to;
                if (typeof(settings.onComplete) == 'function') {
                    settings.onComplete.call(self, value);
                }
            }
        }
        function render(value) {
            var formattedValue = settings.formatter.call(self, value, settings);
            $self.html(formattedValue);
        }
        });
    };
    $.fn.countTo.defaults={
        from:0,               //数字开始的值
        to:0,                 //数字结束的值
        speed:1000,           //设置步长的时间
        refreshInterval:100,  //隔间值
        decimals:0,           //显示小位数
        formatter: formatter, //渲染之前格式化
        onUpdate:null,        //每次更新前的回调方法
        onComplete:null       //完成更新的回调方法
    };
    function formatter(value, settings){
        return value.toFixed(settings.decimals);
    }
    //自定义格式
    $('#count-number').data('countToOptions',{
        formmatter:function(value, options){
            return value.toFixed(options.decimals).replace(/B(?=(?:d{3})+(?!d))/g, ',');
        }
    });
    //定时器
    $('.timer').each(count);
    function count(options){
        var $this=$(this);
        options=$.extend({}, options||{}, $this.data('countToOptions')||{});
        $this.countTo(options);
    }
</script>