jquery插件系列之延迟加载

思路

1. 当浏览器滚动到指定元素进行加载
2. 可以加载多次

先上代码

enum LazyMode {
    once,
    every
}

class LazyItem {
    constructor(
       public element: JQuery,
       public callback: Function,
       public mode: LazyMode = LazyMode.once,
       public diff: number|Function = 0
    ) {
       element.on('lazy-refresh', () => {
           this.refresh();
       });
    }

    private _lastHeight: number; // 上次执行的高度
    /**
     * 重新刷新
     */...