在做组件之前，一般我都是把HTML结构先写出来的，最终我们需要变成这样的结构
<div class="cascader-menus"><ul class="menus"><li>文字</li><li>文字</li><li>文字</li><li>文字</li><li>文字</li><li>文字</li><li>文字</li></ul><ul class="menus"><li>文字</li><li>文字</li><li>文字</li><li>文字</li><li>文字</li><li>文字</li><li>文字</li></ul><ul class="menus"><li>文字</li><li>文字</li><li>文字</li><li>文字</li><li>文字</li><li>文字</li><li>文字</li></ul></div> 然后是样式：
/*这里采用浮动是为了让宽度自适应*/.cascader-menus{float: left;font-size: 0;border: 1px #ccc solid;}/*布局用的inline-block，并且溢出会有滚动条*/.cascader-menus .menus{display: inline-block;min-width: 160px;height: 204px;overflow-y: auto;border-right: 1px #ccc solid;}.cascader-menus .menus:last-child{border-right: none;}.cascader-menus .menus li{font-size: 14px;padding: 0 10px;line-height: 30px;height: 30px;}.cascader-menus .menus li:hover {cursor: pointer;background-color: #eee;}/*点击的时候需要加的样式*/.cascader-menus .menus li.active {background-color: #eee;}数据结构（直接从element-ui复制的）：
var lists = [{value: 'zhinan',label: '指南',children: [{value: 'shejiyuanze',label: '设计原则',children: [{value: 'yizhi',label: '一致'}, {value: 'fankui',label: '反馈'}, {value: 'xiaolv',label: '效率'}, {value: 'kekong',label: '可控'}]},{value: 'daohang',label: '导航',children: [{value: 'cexiangdaohang',label: '侧向导航'},{value: 'dingbudaohang',label: '顶部导航'}]}]},{value: 'zujian',label: '组件',children: [{value: 'basic',label: 'Basic',children: [{value: 'layout',label: 'Layout 布局'}, {value: 'color',label: 'Color 色彩'}, {value: 'typography',label: 'Typography 字体'}, {value: 'icon',label: 'Icon 图标'}, {value: 'button',label: 'Button 按钮'}]}, {value: 'form',label: 'Form',children: [{value: 'radio',label: 'Radio 单选框'}, {value: 'checkbox',label: 'Checkbox 多选框'}, {value: 'input',label: 'Input 输入框'}, {value: 'input-number',label: 'InputNumber 计数器'}, {value: 'select',label: 'Select 选择器'}, {value: 'cascader',label: 'Cascader 级联选择器'}, {value: 'switch',label: 'Switch 开关'}, {value: 'slider',label: 'Slider 滑块'}, {value: 'time-picker',label: 'TimePicker 时间选择器'}, {value: 'date-picker',label: 'DatePicker 日期选择器'}, {value: 'datetime-picker',label: 'DateTimePicker 日期时间选择器'}, {value: 'upload',label: 'Upload 上传'}, {value: 'rate',label: 'Rate 评分'}, {value: 'form',label: 'Form 表单'}]}, {value: 'data',label: 'Data',children: [{value: 'table',label: 'Table 表格'}, {value: 'tag',label: 'Tag 标签'}, {value: 'progress',label: 'Progress 进度条'}, {value: 'tree',label: 'Tree 树形控件'}, {value: 'pagination',label: 'Pagination 分页'}, {value: 'badge',label: 'Badge 标记'}]}, {value: 'notice',label: 'Notice',children: [{value: 'alert',label: 'Alert 警告'}, {value: 'loading',label: 'Loading 加载'}, {value: 'message',label: 'Message 消息提示'}, {value: 'message-box',label: 'MessageBox 弹框'}, {value: 'notification',label: 'Notification 通知'}]}, {value: 'navigation',label: 'Navigation',children: [{value: 'menu',label: 'NavMenu 导航菜单'}, {value: 'tabs',label: 'Tabs 标签页'}, {value: 'breadcrumb',label: 'Breadcrumb 面包屑'}, {value: 'dropdown',label: 'Dropdown 下拉菜单'}, {value: 'steps',label: 'Steps 步骤条'}]}, {value: 'others',label: 'Others',children: [{value: 'dialog',label: 'Dialog 对话框'}, {value: 'tooltip',label: 'Tooltip 文字提示'}, {value: 'popover',label: 'Popover 弹出框'}, {value: 'card',label: 'Card 卡片'}, {value: 'carousel',label: 'Carousel 走马灯'}, {value: 'collapse',label: 'Collapse 折叠面板'}]}]},{value: 'ziyuan',label: '资源',children: [{value: 'axure',label: 'Axure Components'}, {value: 'sketch',label: 'Sketch Templates'}, {value: 'jiaohu',label: '组件交互文档'}]},{"value": 1, label: 'xxx'},
]然后是JS:
//构造函数function Cascader(id,data,fn){//把创建好的“联级选择器”插入到哪个元素内this.$box = $("#"+id);//data: 是要填充的数据this.init(data);//对外提供的接口函数this.clickHandle = fn || function(){};//最外层的容器,后期需要把createEl()方法创建的内容都插入到这里面的this.$wrap = null;}Cascader.prototype = {constructor: Cascader,init: function(data){var This = this;this.$wrap = $("<div class='cascader-menus'></div>")//创建里面的元素this.createEl(data,function($ul){This.$wrap.append($ul);This.$box.append(This.$wrap)});console.log(data)},createEl: function(data,fn) {var This = this;//创建完成以后回调函数var fn = fn || function(){};var $ul = $("<ul class='menus'></ul>");//创建li，并把li插入到ul中for (var i=0;i<data.length;i++) {var $li = $("<li>"+ data[i].label +"</li>");//给每一个Li加点击事件，点击以后显示子菜单,这里最好采用闭包的形式，不然i传递不进去，当然也可以用es6的let（不过这里没有bable，浏览器会不支持let的，在vue-cli中的话就没问题了）(function(i){$li.click(function(){$(this).addClass('active').siblings().removeClass('active');//先需要清除掉后面所有的菜单$ul.nextAll().remove();if (data[i].children && data[i].children.length) {//创建子菜单This.createEl(data[i].children,function(ul){//把创建好的子菜单插入到上一个菜单的后面$ul.after(ul);});}//对外提供的点击接口函数，并把数据给传递出去This.clickHandle(data[i]);})})(i)$ul.append($li);}//创建完成以后回调函数fn($ul)}}使用：
在html中先写一个div
<div id="box"></div>//调用var c1 = new Cascader("box",lists,function(mes){console.log(mes)});