移动端回到顶部

CSS：

.goTop{
			position: absolute;
		    bottom: -50px;
		    right: 15px;
		    color: #fff;
		    z-index: 99;
		    width: 50px;
		    height: 50px;
		    border-radius: 50%;
		    background: rgba(34,34,34,0.8);
		    text-align: center;
		    -webkit-transition: all .6s;
            transition: all .6s;
		}
		.goTop .icon-arrowstopfloat{
			position: relative;
		    top: 8px;
		    display: block;
		}
	    .goTop .TOP {
			display: block;
			line-height: 22px;
		}
		.goTop.on{
			bottom: 70px;
		}

HTML：

<div class="goTop" tapmode onclick="goTop()">
		    <span class="iconfont icon-arrowstopfloat fs14"></span>
		    <span class="TOP fs17">TOP</span>
		</div>

JS：
    要先引入插件

<script type="text/javascript" src="../../script/iscroll-probe.min.js"></script>
function goTop(){
		IScroll.scrollTo(0, 0, 300)
	}