JS判断当前DOM树是否加载完毕

/**
 * @function Monitor whether the document tree is loaded.
 * @param fn
 */
function domReady(fn) {
    if (document.addEventListener) { // 标准浏览器
        document.addEventListener('DOMContentLoaded', function () { //注销时间，避免重复触发
            document.removeEventListener('DOMContentLoaded', arguments.callee, false);
            fn(); // 运行函数
        }, false);
    } else if (document.attachEvent) { // IE浏览器
        document.attachEvent('onreadystatechange', function () {
            if (document.readyState == 'complete') {
                document.detachEvent('onreadystatechange', arguments.callee);
                fn(); // 函数运行
            }
        });
    }
}

domReady(loadStart);