案例-使用面向对象写 Tab 栏

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(); // 加载即调用
    }
    // init 初始化操作，让相关的元素绑定事件
    init() {
        this.updateNode();
        this.add.onclick = this.addTab;
        for (var i = 0; i < this.lis.length; i++) {
            this.lis[i].index = i;
            this.lis[i].onclick = this.toggleTab;
            this.remove[i].onclick = this.removeTab;
            this.spans[i].ondbclick = this.editTab;
            this.sections[i].ondbclick = this.editTab;
        }
    }
    updateNode() {
        this.lis = this.main.querySelectorAll('li');
        this.sections = this.main.querySelectorAll('section');
        this.remove = this.main.querySelectorAll('.icon-guanbi');
        this.spans = this.main.querySelectorAll('.firstnav li span:nth-child(1)');
    }
    // 切换功能
    toggleTab() {
        console.log(this.index);
        that.clearClass();
        this.className = 'liactive';
        that.sections[this.index].className = 'conactive';
    }
    clearClass() {
        for (var i = 0; i < this.lis.length; i++) {
            this.lis[i].className = '';
            this.sections[i].className = '';
        }
    }
    // 添加功能
    addTab() {
        that.clearClass();
        var li = '<li class="liactive"><span>新选项卡</span><span class="iconfont icon-guanbi"></span></li>';
        var section = '<section class="conactive">测试</section>';
        that.ul.insertAdjacentHTML('beforeend', li);
        that.fsection.insertAdjacentHTML('beforeend', section);
        that.init();
    }
    // 删除功能
    removeTab(e) {
        e.stopPropagation();
        var index = this.parentNode.index;
        that.lis[index].remove();
        that.sections[index].remove();
        that.init();
        if (document.querySelector('liactive')) return;
        index--;
        that.lis[index] && that.lis[index].click(); // 模拟手动调用点击事件
    }
    // 修改功能
    editTab() {
        var str = this.innerHTML;
        // 双击禁止选中文字
        window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty();
        this.innerHTML = '<input type="text" />';
        var input = this.children[0];
        input.value = str;
        input.select(); // 选中文本框中文字
        input.onblur = function() {
            this.parentNode.innerHTML = this.value;
        }
        input.onkeyup = function(e) {
            if (e.keyCode == 13) {
                this.blur();
            }
        }
    }
}
new Tab('#tab');