ES6面向对象 动态添加标签页

var that;
class Tab {
    constructor(id) {
        that = this;
        this.main = document.querySelector(id);        
        this.add = this.main.querySelector(".tabadd");
        this.ul = this.main.querySelector('.firstnav ul:first-child');
        this.fsection = this.main.querySelector('.tabscon');
        this.init();
    }
    init() {
        this.updateNode();
        //init 初始化操作，绑定相关的绑定事件 
        this.add.onclick = this.addTab;
        for (var i = 0; i < this.lis.length; i++) {
            this.lis[i].index = i;//添加一个索引号
            this.lis[i].onclick = this.toggleTab;
            this.remove[i].onclick = this.removeTab;
            this.spans[i].ondblclick = this.editTab;
            this.sections[i].ondblclick = this.editTab;
        }
    }
    //动态添加元素，需要重新获取对应的元素
    updateNode() {
        this.lis = this.main.querySelectorAll("li");
        this.sections = this.main.querySelectorAll("section");
        this.remove = this.main.querySelectorAll('.iconfont');
        this.spans = this.main.querySelectorAll('.firstnav li span:first-child');
    }
    //1.切换功能
    toggleTab() {
        that.clearClass();
        this.className = 'liactive';
        that.sections[this.index].className = 'conactive';
    }
    //清楚所有li和scction的类
    clearClass() {
        for (var i = 0; i < this.lis.length; i++) {
            this.lis[i].className = '';
            that.sections[i].className = '';
        }
    }
    //2.添加功能
    addTab() {
        that.clearClass();
        var random = Math.random();
        var li = '<li class="liactive"><span>新加标签</span><span class="iconfont"><img src="https://mychalk.oss-cn-hangzhou.aliyuncs.com/images/cc.png" /></span></li>';
        var section = '<section class="conactive">内容 ' + random + '</section>';
        that.ul.insertAdjacentHTML('beforeend', li);
        that.fsection.insertAdjacentHTML('beforeend', section);
        that.init();
    }
    //3.删除功能
    removeTab(e) {
        e.stopPropagation();//阻止冒泡 防止出发li 的切换事件
        var index = this.parentNode.index;//获取索引号等于父元素的索引号
        //根据索引号删除对应的li和section  remove（）方法可以直接删除指定元素
        that.lis[index].remove();
        that.sections[index].remove();
        that.init();
        //当删除的不是选中状态的li时，原来的选中状态保持不变
        if (document.querySelector('.liactive')) return;
        //当删除选中状态的li时，前一个li处于选定状态
        index--;
        //手动调用点击事件，如果存在索引号则触发，否则不触发点击事件
        that.lis[index] && that.lis[index].click();
    }
    //4.修改功能
    editTab() {
        var str = this.innerHTML;
        //双击禁止选定文字
        window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty();
        this.innerHTML = '<input type="text" />';
        var input = this.children[0];//定义inpot等于span的第一个子元素
        input.value = str;
        //自动选定文本框内所有文字
        input.select();
        //当我们离开文本框时，将文本框的值给span
        input.onblur = function () {
            this.parentNode.innerHTML = this.value;
        }
        input.onkeyup = function (e) {
            if (e.keyCode === 13) {
                //按下回车键 手动调用表单失去焦点事件
                this.blur();
            }
        }
    }
}
new Tab("#tab");//实例一个对象