npm install react-lazyload-image --save
import LazyImg from 'react-lazyload-image'
<LazyImg src='imgurl' alt='lazyimg' />
@param src {!url}
@param alt {!string}
@param transElement {?selector} 需要绑定transitionend触发图片加载的dom selector，为空则不监听该事件
@param scroller {?selector} 需要绑定scroll触发图片加载的dom selector，默认为document