iscroll动态加载数据完美解决方案

<div id="wrapper" class="margin-b90">
        <div id="scroller">
            <div id="pullDown">
                <span class="pullDownLabel" style="text-align: center;">加载中...</span>
            </div>
            <div class="sps_itemBox ">
                <div class="list_show">
                    <ul id="ulList"></ul>
                </div>
            </div>

            <div id="pullUp">
                <span class="pullUpLabel" style="text-align: center;">上拉加载...</span>
            </div>
        </div>
    </div>

// iScroll 滚动条/上拉刷新/下拉加载
var myScroll,
    pullDownEl,
    pullDownOffset,
    pullUpEl,
    pullUpOffset;

function loaded() {
    pullDownEl = document.getElementById('pullDown');
    pullDownOffset = pullDownEl.offsetHeight;
    pullUpEl = document.getElementById('pullUp');
    pullUpOffset = pullUpEl.offsetHeight;
    myScroll = new iScroll('wrapper', {
        useTransition: false,
        topOffset: pullDownOffset,
        btnOffset: pullUpOffset,
        hideScrollbar: true,
        fadeScrollbar: true,
        onRefresh: function () {
            if (pullDownEl.className.match('loading')) {
                pullDownEl.className = '';
                //pullDownEl.querySelector('.pullDownLabel').innerHTML = '下拉刷新...';
                pullDownEl.querySelector('.pullDownLabel').innerHTML = '数据更新时间：' + updateDatetime;
            } else if (pullUpEl.className.match('loading')) {
                pullUpEl.className = '';
                pullUpEl.querySelector('.pullUpLabel').innerHTML = '上拉加载...';
            }
        },
        onScrollMove: function () {
            if (this.y > 5 && !pullDownEl.className.match('flip')) {
                pullDownEl.className = 'flip';
                //pullDownEl.querySelector('.pullDownLabel').innerHTML = '释放刷新...';
                pullDownEl.querySelector('.pullDownLabel').innerHTML = '数据更新时间：' + updateDatetime;
                this.minScrollY = 0;
            } else if (this.y < 5 && pullDownEl.className.match('flip')) {
                pullDownEl.className = '';
                //pullDownEl.querySelector('.pullDownLabel').innerHTML = '下拉刷新...';
                pullDownEl.querySelector('.pullDownLabel').innerHTML = '数据更新时间：' + updateDatetime;
                this.minScrollY = -pullDownOffset;
            } else if (this.y < (this.maxScrollY - pullUpOffset - 40) && !pullUpEl.className.match('flip')) {
                pullUpEl.className = 'flip';
                pullUpEl.querySelector('.pullUpLabel').innerHTML = '释放加载...';
                this.maxScrollY = this.maxScrollY - pullUpOffset;
            }
            //else if (this.y > (this.maxScrollY - pullUpOffset) && pullUpEl.className.match('flip')) {
            //    pullUpEl.className = '';
            //    pullUpEl.querySelector('.pullUpLabel').innerHTML = '上拉加载...';
            //    //this.maxScrollY = pullUpOffset;
            //}
        },
        onScrollEnd: function () {
            if (pullDownEl.className.match('flip')) {
                pullDownEl.className = 'loading';
                //pullDownEl.querySelector('.pullDownLabel').innerHTML = '数据刷新中...';
                pullDownEl.querySelector('.pullDownLabel').innerHTML = '数据更新时间：' + updateDatetime;
                myScroll.refresh();
            } else if (pullUpEl.className.match('flip')) { 
                pullUpEl.className = 'loading';
                pullUpEl.querySelector('.pullUpLabel').innerHTML = '数据加载中...';
                setTimeout(function () { myScroll.refresh(); }, 3000);

            }
        }
    });
}
document.addEventListener('touchmove', function (e) { e.preventDefault(); }, false);
document.addEventListener('DOMContentLoaded', function () { setTimeout(loaded, 200); }, false);

/* iScroll */
#wrapper{width:100%; position:absolute; top:0; bottom:0; z-index:1; overflow:hidden;}
#scroller{
    width:100%; position:absolute; z-index:1;
    -webkit-touch-callout:none; -webkit-tap-highlight-color:rgba(0,0,0,0);
}
#pullDown,
#pullUp{padding:15px 0 15px 60px; font-size:14px; line-height:27px; color:#303030;}
#pullDown{background:url(../images/loadBottom.png) no-repeat 30px center; background-size:27px 27px;}
#pullUp{background:url(../images/loadTop.png) no-repeat 30px center; background-size:27px 27px;}
#pullDown.flip{background:url(../images/loadTop.png) no-repeat 30px center; background-size:27px 27px;}
#pullUp.flip{background:url(../images/loadBottom.png) no-repeat 30px center; background-size:27px 27px;}
#pullDown.loading,
#pullUp.loading{background:url(../images/loading.gif) no-repeat 30px center; background-size:25px 27px;}
/* iScroll end */