html5监控某个dom变化

var targetSecondNode = $(".secondList")[0];//要监控的dom对象
    var obSecondServer = new MutationObserver(function (mutations) {　　　　　　　//dom变化回调的函数
            $(".secondList .item-list div:first").addClass("active");
            $(".secondList .item-list div:first").click();
    });
    obSecondServer.observe(targetSecondNode, { attributes: true, childList: true, subtree: true });