Vue基础与常用指令，Element基础

1.vue快速入门

vue概述

Vue是一套构建用户界面的渐进式前端框架

只关注视图层，并且非常容易学习，还可以很方便的与其它库或已有项目整合

通过尽可能简单的API来实现响应数据的绑定和组合的视图组件

特点

易用：在有HTMLCSSJavaScript的基础上，快速上手。

灵活：简单小巧的核心，渐进式技术栈，足以应付任何规模的应用。

性能：20kbmin+gzip运行大小、超快虚拟DOM、最省心的优化

快速入门

1.下载和引入vue.js文件

2.编写入门程序

视图：负责页面渲染，主要由HTML+CSS构成

脚本：负责业务数据模型（Model）以及数据的处理逻辑


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>快速入门title>
head>
<body>
    
    <div id="div">
        {{msg}}
    div>
body>
<script src="vue.js">script>
<script>
    //脚本
    new Vue({
        el:"#div",
        data:{
            msg:"Hello Vue"
        }
    });
script>
html>

Vue 核心对象：每一个 Vue 程序都是从一个 Vue 核心对象开始的


let vm = new Vue({
	选项列表;
});

选项列表

el选项：用于接收获取到页面中的元素。(根据常用选择器获取)

data选项：用于保存当前Vue对象中的数据。在视图中声明的变量需要在此处赋值

methods选项：用于定义方法。方法可以直接通过对象名调用，this代表当前Vue对象

数据绑定

在视图部分获取脚本部分的数据。

快速入门升级


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>快速入门升级title>
head>
<body>
    
    <div id="div">
        <div>姓名：{{name}}div>
        <div>班级：{{classRoom}}div>
        <button onclick="hi()">打招呼button>
        <button onclick="update()">修改班级button>
    div>
body>
<script src="vue.js">script>
<script>
    // 脚本
    let vm = new Vue({
        el:"#div",
        data:{
            name:"张三",
            classRoom:"一班"
        },
        methods:{
            study(){
                alert(this.name + "正在" + this.classRoom + "好好学习!");
            }
        }
    });
 
    //定义打招呼方法
    function hi(){
        vm.study();
    }
 
    //定义修改班级
    function update(){
        vm.classRoom = "二班";
    }
script>
html>

2.vue常用指令

1.指令的介绍

指令：是带有 v- 前缀的特殊属性，不同指令具有不同含义。例如 v-html，v-if，v-for

使用指令时，通常编写在标签的属性上，值可以使用 JS 的表达式

指令：vue框架定义的，一些标签的自定义的属性

常用指令

指令	作用
v-html	把文本解析为HTML代码
v-bind	为HTML标签绑定属性值
v-if	条件性的渲染某元素，判定为true时渲染，否则不渲染
v-else
v-else-if
v-show	根据条件展示某元素，区别在于切换的是display属性的值
v-for	列表渲染，遍历容器的元素或者对象的属性
v-on	为HTML标签绑定事件
v-model	为表单元素上创建双向数据绑定

2.文本插值

v-html：把文本解析为 HTML 代码


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>文本插值title>
head>
<body>
    <div id="div">
        <div>{{msg}}div>
        <div v-html="msg">div>
    div>
body>
<script src="vue.js">script>
<script>
    new Vue({
        el:"#div",
        data:{
            msg:"Hello Vue"
        }
    });
script>
html>

3.绑定属性

v-bind：为 HTML 标签绑定属性值


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>绑定属性title>
    <style>
        .my{
            border: 1px solid red;
        }
    style>
head>
<body>
    <div id="div">
        <a v-bind:href="url">百度一下a>
        <br>
        <a :href="url">百度一下a>
        <br>
        <div :class="cls">我是divdiv>
    div>
body>
<script src="vue.js">script>
<script>
    new Vue({
        el:"#div",
        data:{
            url:"https://www.baidu.com",
            cls:"my"
        }
    });
script>
html>

4.条件渲染

v-if：条件性的渲染某元素，判定为真时渲染,否则不渲染

v-else：条件性的渲染

v-else-if：条件性的渲染

v-show：根据条件展示某元素，区别在于切换的是display属性的值


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>条件渲染title>
head>
<body>
    <div id="div">
        
        <div v-if="num % 3 == 0">div1div>
        <div v-else-if="num % 3 == 1">div2div>
        <div v-else="num % 3 == 2">div3div>
        
        <div v-show="flag">div4div>
    div>
body>
<script src="vue.js">script>
<script>
    new Vue({
        el:"#div",
        data:{
            num:1,
            flag:false
        }
    });
script>
html>

5.列表渲染

v-for：列表渲染，遍历容器的元素或者对象的属性


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>列表渲染title>
head>
<body>
    <div id="div">
        <ul>
            <li v-for="name in names">
                {{name}}
            li>
            <li v-for="value in student">
                {{value}}
            li>
        ul>
    div>
body>
<script src="vue.js">script>
<script>
    new Vue({
        el:"#div",
        data:{
            names:["张三","李四","王五"],
            student:{
                name:"张三",
                age:23
            }
        }
    });
script>
html>

6.事件绑定

v-on：为 HTML 标签绑定事件


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>事件绑定title>
head>
<body>
    <div id="div">
        <div>{{name}}div>
        <button v-on:click="change()">改变div的内容button>
        <button v-on:dblclick="change()">改变div的内容button>
 
        <button @click="change()">改变div的内容button>
    div>
body>
<script src="vue.js">script>
<script>
    new Vue({
        el:"#div",
        data:{
            name:"周杰伦"
        },
        methods:{
            change(){
                this.name = "王力宏"
            }
        }
    });
script>
html>

7.表单绑定

表单绑定

v-model：在表单元素上创建双向数据绑定

双向数据绑定

更新data数据，页面中的数据也会更新

更新页面数据，data数据也会更新

MVVM模型(ModelViewViewModel)：是MVC模式的改进版

在前端页面中，JS对象表示Model，页面表示View，两者做到了最大限度的分离

将Model和View关联起来的就是ViewModel，它是桥梁

ViewModel负责把Model的数据同步到View显示出来，还负责把View修改的数据同步回Model


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>表单绑定title>
head>
<body>
    <div id="div">
        <form autocomplete="off">
            姓名：<input type="text" name="username" v-model="username">
            <br>
            年龄：<input type="number" name="age" v-model="age">
        form>
    div> 
body>
<script src="vue.js">script>
<script>
    new Vue({
        el:"#div",
        data:{
            username:"张三",
            age:23
        }
    });
script>
html>

3.Element基本使用

1.Element概述

Element：网站快速成型工具。是饿了么公司前端开发团队提供的一套基于Vue的网站组件库。

使用Element前提必须要有Vue。

组件：组成网页的部件，例如超链接、按钮、图片、表格等等

Element官网：https://element.eleme.cn/#/zh-CN

2.Element快速入门

1.下载 Element 核心库。

2.引入 Element 样式文件。

3.引入 Vue 核心 js 文件。

4.引入 Element 核心 js 文件。

5.编写按钮标签。

6.通过 Vue 核心对象加载元素


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>快速入门title>
    <link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
    <script src="vue.js">script>
    <script src="element-ui/lib/index.js">script>
head>
<body>
    <button>我是按钮button>
    <br>
    <div id="div">
        <el-row>
            <el-button>默认按钮el-button>
            <el-button type="primary">主要按钮el-button>
            <el-button type="success">成功按钮el-button>
            <el-button type="info">信息按钮el-button>
            <el-button type="warning">警告按钮el-button>
            <el-button type="danger">危险按钮el-button>
          el-row>
          <br>
          <el-row>
            <el-button plain>朴素按钮el-button>
            <el-button type="primary" plain>主要按钮el-button>
            <el-button type="success" plain>成功按钮el-button>
            <el-button type="info" plain>信息按钮el-button>
            <el-button type="warning" plain>警告按钮el-button>
            <el-button type="danger" plain>危险按钮el-button>
          el-row>
          <br>
          <el-row>
            <el-button round>圆角按钮el-button>
            <el-button type="primary" round>主要按钮el-button>
            <el-button type="success" round>成功按钮el-button>
            <el-button type="info" round>信息按钮el-button>
            <el-button type="warning" round>警告按钮el-button>
            <el-button type="danger" round>危险按钮el-button>
          el-row>
          <br>
          <el-row>
            <el-button icon="el-icon-search" circle>el-button>
            <el-button type="primary" icon="el-icon-edit" circle>el-button>
            <el-button type="success" icon="el-icon-check" circle>el-button>
            <el-button type="info" icon="el-icon-message" circle>el-button>
            <el-button type="warning" icon="el-icon-star-off" circle>el-button>
            <el-button type="danger" icon="el-icon-delete" circle>el-button>
          el-row>
    div>
body>
<script>
    new Vue({
        el:"#div"
    });
script>
html>

3.基础布局

将页面分成最多 24 个部分，自由切分


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>基础布局title>
    <link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
    <script src="vue.js">script>
    <script src="element-ui/lib/index.js">script>
    <style>
        .el-row {
            /* 行距为20px */
            margin-bottom: 20px;
        }
        .bg-purple-dark {
            background: red;
        }
        .bg-purple {
            background: blue;
        }
        .bg-purple-light {
            background: green;
        }
        .grid-content {
            /* 边框圆润度 */
            border-radius: 4px;
            /* 行高为36px */
            min-height: 36px;
        }
      style>
head>
<body>
    <div id="div">
        <el-row>
            <el-col :span="24"><div class="grid-content bg-purple-dark">div>el-col>
          el-row>
          <el-row>
            <el-col :span="12"><div class="grid-content bg-purple">div>el-col>
            <el-col :span="12"><div class="grid-content bg-purple-light">div>el-col>
          el-row>
          <el-row>
            <el-col :span="8"><div class="grid-content bg-purple">div>el-col>
            <el-col :span="8"><div class="grid-content bg-purple-light">div>el-col>
            <el-col :span="8"><div class="grid-content bg-purple">div>el-col>
          el-row>
          <el-row>
            <el-col :span="6"><div class="grid-content bg-purple">div>el-col>
            <el-col :span="6"><div class="grid-content bg-purple-light">div>el-col>
            <el-col :span="6"><div class="grid-content bg-purple">div>el-col>
            <el-col :span="6"><div class="grid-content bg-purple-light">div>el-col>
          el-row>
          <el-row>
            <el-col :span="4"><div class="grid-content bg-purple">div>el-col>
            <el-col :span="4"><div class="grid-content bg-purple-light">div>el-col>
            <el-col :span="4"><div class="grid-content bg-purple">div>el-col>
            <el-col :span="4"><div class="grid-content bg-purple-light">div>el-col>
            <el-col :span="4"><div class="grid-content bg-purple">div>el-col>
            <el-col :span="4"><div class="grid-content bg-purple-light">div>el-col>
          el-row>
    div>
body>
<script>
    new Vue({
        el:"#div"
    });
script>
html>

4.容器布局

将页面分成头部区域、侧边栏区域、主区域、底部区域


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>容器布局title>
    <link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
    <script src="vue.js">script>
    <script src="element-ui/lib/index.js">script>
    <style>
        .el-header, .el-footer {
            background-color: #d18e66;
            color: #333;
            text-align: center;
            height: 100px;
        }
        .el-aside {
            background-color: #55e658;
            color: #333;
            text-align: center;
            height: 580px;
        }
        .el-main {
            background-color: #5fb1f3;
            color: #333;
            text-align: center;
            height: 520px;
        }
    style>
head>
<body>
    <div id="div">
        <el-container>
            <el-header>头部区域el-header>
            <el-container>
              <el-aside width="200px">侧边栏区域el-aside>
              <el-container>
                <el-main>主区域el-main>
                <el-footer>底部区域el-footer>
              el-container>
            el-container>
          el-container>
    div>
body>
<script>
    new Vue({
        el:"#div"
    });
script>
html>

5.表单组件

表单：由输入框、下拉列表、单选框、多选框等控件组成，用以收集、校验、提交数据


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>表单组件title>
    <link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
    <script src="vue.js">script>
    <script src="element-ui/lib/index.js">script>
head>
<body>
    <div id="div">
        <el-form :model="ruleForm" :rules="rules" ref="ruleForm" label-width="100px" class="demo-ruleForm">
            <el-form-item label="活动名称" prop="name">
              <el-input v-model="ruleForm.name">el-input>
            el-form-item>
            <el-form-item label="活动区域" prop="region">
              <el-select v-model="ruleForm.region" placeholder="请选择活动区域">
                <el-option label="区域一" value="shanghai">el-option>
                <el-option label="区域二" value="beijing">el-option>
              el-select>
            el-form-item>
            <el-form-item label="活动时间" required>
              <el-col :span="11">
                <el-form-item prop="date1">
                  <el-date-picker type="date" placeholder="选择日期" v-model="ruleForm.date1" style="width: 100%;">el-date-picker>
                el-form-item>
              el-col>
              <el-col class="line" :span="2">-el-col>
              <el-col :span="11">
                <el-form-item prop="date2">
                  <el-time-picker placeholder="选择时间" v-model="ruleForm.date2" style="width: 100%;">el-time-picker>
                el-form-item>
              el-col>
            el-form-item>
            <el-form-item label="即时配送" prop="delivery">
              <el-switch v-model="ruleForm.delivery">el-switch>
            el-form-item>
            <el-form-item label="活动性质" prop="type">
              <el-checkbox-group v-model="ruleForm.type">
                <el-checkbox label="美食/餐厅线上活动" name="type">el-checkbox>
                <el-checkbox label="地推活动" name="type">el-checkbox>
                <el-checkbox label="线下主题活动" name="type">el-checkbox>
                <el-checkbox label="单纯品牌曝光" name="type">el-checkbox>
              el-checkbox-group>
            el-form-item>
            <el-form-item label="特殊资源" prop="resource">
              <el-radio-group v-model="ruleForm.resource">
                <el-radio label="线上品牌商赞助">el-radio>
                <el-radio label="线下场地免费">el-radio>
              el-radio-group>
            el-form-item>
            <el-form-item label="活动形式" prop="desc">
              <el-input type="textarea" v-model="ruleForm.desc">el-input>
            el-form-item>
            <el-form-item>
              <el-button type="primary" @click="submitForm('ruleForm')">立即创建el-button>
              <el-button @click="resetForm('ruleForm')">重置el-button>
            el-form-item>
          el-form>
    div>
body>
<script>
    new Vue({
        el:"#div",
        data:{
            ruleForm: {
                name: '',
                region: '',
                date1: '',
                date2: '',
                delivery: false,
                type: [],
                resource: '',
                desc: ''
                },
        rules: {
          name: [
            { required: true, message: '请输入活动名称', trigger: 'blur' },
            { min: 3, max: 5, message: '长度在 3 到 5 个字符', trigger: 'blur' }
          ],
          region: [
            { required: true, message: '请选择活动区域', trigger: 'change' }
          ],
          date1: [
            { type: 'date', required: true, message: '请选择日期', trigger: 'change' }
          ],
          date2: [
            { type: 'date', required: true, message: '请选择时间', trigger: 'change' }
          ],
          type: [
            { type: 'array', required: true, message: '请至少选择一个活动性质', trigger: 'change' }
          ],
          resource: [
            { required: true, message: '请选择活动资源', trigger: 'change' }
          ],
          desc: [
            { required: true, message: '请填写活动形式', trigger: 'blur' }
          ]
        }
        },
        methods:{
            submitForm(formName) {
                this.$refs[formName].validate((valid) => {
                if (valid) {
                    alert('submit!');
                } else {
                    console.log('error submit!!');
                    return false;
                }
                });
            },
            resetForm(formName) {
                this.$refs[formName].resetFields();
            }
        }
    });
script>
html>

6.表格组件

表格：用于展示多条结构类似的数据，可对数据进行编辑、删除或其他自定义操作


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>表格组件title>
    <link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
    <script src="vue.js">script>
    <script src="element-ui/lib/index.js">script>
head>
<body>
    <div id="div">
        <template>
            <el-table
              :data="tableData"
              style="width: 100%">
              <el-table-column
                prop="date"
                label="日期"
                width="180">
              el-table-column>
              <el-table-column
                prop="name"
                label="姓名"
                width="180">
              el-table-column>
              <el-table-column
                prop="address"
                label="地址">
              el-table-column>
 
              <el-table-column
                label="操作"
                width="180">
                <el-button type="warning">编辑el-button>
                <el-button type="danger">删除el-button>
              el-table-column>
            el-table>
          template>
    div>
body>
<script>
    new Vue({
        el:"#div",
        data:{
            tableData: [{
                date: '2016-05-02',
                name: '王小虎',
                address: '上海市普陀区金沙江路 1518 弄'
            }, {
                date: '2016-05-04',
                name: '王小虎',
                address: '上海市普陀区金沙江路 1517 弄'
            }, {
                date: '2016-05-01',
                name: '王小虎',
                address: '上海市普陀区金沙江路 1519 弄'
            }, {
                date: '2016-05-03',
                name: '王小虎',
                address: '上海市普陀区金沙江路 1516 弄'
            }]
        }
    });
script>
html>

7.顶部导航栏组件


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>顶部导航栏title>
    <link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
    <script src="vue.js">script>
    <script src="element-ui/lib/index.js">script>
head>
<body>
    <div id="div">
      <el-menu
      :default-active="activeIndex2"
      class="el-menu-demo"
      mode="horizontal"
      @select="handleSelect"
      background-color="#545c64"
      text-color="#fff"
      active-text-color="#ffd04b">
      <el-menu-item index="1">处理中心el-menu-item>
      <el-submenu index="2">
        <template slot="title">我的工作台template>
        <el-menu-item index="2-1">选项1el-menu-item>
        <el-menu-item index="2-2">选项2el-menu-item>
        <el-menu-item index="2-3">选项3el-menu-item>
        <el-submenu index="2-4">
          <template slot="title">选项4template>
          <el-menu-item index="2-4-1">选项1el-menu-item>
          <el-menu-item index="2-4-2">选项2el-menu-item>
          <el-menu-item index="2-4-3">选项3el-menu-item>
        el-submenu>
      el-submenu>
      <el-menu-item index="3" disabled>消息中心el-menu-item>
      <el-menu-item index="4"><a href="https://www.ele.me" target="_blank">订单管理a>el-menu-item>
    el-menu>
    div>
body>
<script>
    new Vue({
        el:"#div"
    });
script>
html>

8.侧边导航栏组件


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>侧边导航栏title>
    <link rel="stylesheet" href="element-ui/lib/theme-chalk/index.css">
    <script src="vue.js">script>
    <script src="element-ui/lib/index.js">script>
head>
<body>
    <div id="div">
      <el-col :span="6">
        <el-menu
          default-active="2"
          class="el-menu-vertical-demo"
          @open="handleOpen"
          @close="handleClose"
          background-color="#545c64"
          text-color="#fff"
          active-text-color="#ffd04b">
          <el-submenu index="1">
            <template slot="title">
              <i class="el-icon-location">i>
              <span>导航一span>
            template>
            <el-menu-item-group>
              <template slot="title">分组一template>
              <el-menu-item index="1-1">选项1el-menu-item>
              <el-menu-item index="1-2">选项2el-menu-item>
            el-menu-item-group>
            <el-menu-item-group title="分组2">
              <el-menu-item index="1-3">选项3el-menu-item>
            el-menu-item-group>
            <el-submenu index="1-4">
              <template slot="title">选项4template>
              <el-menu-item index="1-4-1">选项1el-menu-item>
            el-submenu>
          el-submenu>
          <el-menu-item index="2">
            <i class="el-icon-menu">i>
            <span slot="title">导航二span>
          el-menu-item>
          <el-menu-item index="3" disabled>
            <i class="el-icon-document">i>
            <span slot="title">导航三span>
          el-menu-item>
          <el-menu-item index="4">
            <i class="el-icon-setting">i>
            <span slot="title">导航四span>
          el-menu-item>
        el-menu>
      el-col>
    div>
body>
<script>
    new Vue({
        el:"#div"
    });
script>
html>

4.vue高级使用

1.自定义组件

组件其实就是自定义的标签。例如就是对"

});
new Vue({
el:"#div"
});
script>
html>

2.vue的生命周期

生命周期的八个状态

状态	阶段周期
beforeCreate	创建前
created	创建后
beforeMount	载入前
mounted	载入后
beforeUpdate	更新前
updated	更新后
beforeDestory	销毁前
destoryed	销毁后


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>生命周期title>
    <script src="vue.js">script>
head>
<body>
    <div id="app">
        {{message}}
    div>
body>
<script>
    let vm = new Vue({
				el: '#app',
				data: {
					message: 'Vue的生命周期'
				},
				beforeCreate: function() {
					console.group('------beforeCreate创建前状态------');
					console.log("%c%s", "color:red", "el     : " + this.$el); //undefined
					console.log("%c%s", "color:red", "data   : " + this.$data); //undefined 
					console.log("%c%s", "color:red", "message: " + this.message);//undefined
				},
				created: function() {
					console.group('------created创建完毕状态------');
					console.log("%c%s", "color:red", "el     : " + this.$el); //undefined
					console.log("%c%s", "color:red", "data   : " + this.$data); //已被初始化 
					console.log("%c%s", "color:red", "message: " + this.message); //已被初始化
				},
				beforeMount: function() {
					console.group('------beforeMount挂载前状态------');
					console.log("%c%s", "color:red", "el     : " + (this.$el)); //已被初始化
					console.log(this.$el);
					console.log("%c%s", "color:red", "data   : " + this.$data); //已被初始化  
					console.log("%c%s", "color:red", "message: " + this.message); //已被初始化  
				},
				mounted: function() {
					console.group('------mounted 挂载结束状态------');
					console.log("%c%s", "color:red", "el     : " + this.$el); //已被初始化
					console.log(this.$el);
					console.log("%c%s", "color:red", "data   : " + this.$data); //已被初始化
					console.log("%c%s", "color:red", "message: " + this.message); //已被初始化 
				},
				beforeUpdate: function() {
					console.group('beforeUpdate 更新前状态===============》');
					let dom = document.getElementById("app").innerHTML;
					console.log(dom);
					console.log("%c%s", "color:red", "el     : " + this.$el);
					console.log(this.$el);
					console.log("%c%s", "color:red", "data   : " + this.$data);
					console.log("%c%s", "color:red", "message: " + this.message);
				},
				updated: function() {
					console.group('updated 更新完成状态===============》');
					let dom = document.getElementById("app").innerHTML;
					console.log(dom);
					console.log("%c%s", "color:red", "el     : " + this.$el);
					console.log(this.$el);
					console.log("%c%s", "color:red", "data   : " + this.$data);
					console.log("%c%s", "color:red", "message: " + this.message);
				},
				beforeDestroy: function() {
					console.group('beforeDestroy 销毁前状态===============》');
					console.log("%c%s", "color:red", "el     : " + this.$el);
					console.log(this.$el);
					console.log("%c%s", "color:red", "data   : " + this.$data);
					console.log("%c%s", "color:red", "message: " + this.message);
				},
				destroyed: function() {
					console.group('destroyed 销毁完成状态===============》');
					console.log("%c%s", "color:red", "el     : " + this.$el);
					console.log(this.$el);
					console.log("%c%s", "color:red", "data   : " + this.$data);
					console.log("%c%s", "color:red", "message: " + this.message);
				}
			});
 
			// 销毁Vue对象
			//vm.$destroy();
			//vm.message = "hehe";	// 销毁后 Vue 实例会解绑所有内容
 
			// 设置data中message数据值
			vm.message = "good...";
script>
html>

3.异步操作

在Vue中发送异步请求，本质上还是AJAX。我们可以使用axios这个插件来简化操作

使用步骤

1.引入axios核心js文件

2.调用axios对象的方法来发起异步请求

3.调用axios对象的方法来处理响应的数据

方法名	作用
get(请求的资源路径与请求的参数)	发起GET请求
post(请求的资源路径,请求的参数)	发起POST方式请求
then(response)	请求成功后的回调函数，通过response获取响应的数据
catch(error)	请求失败后的回调函数，通过error获取错误信息


html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>异步操作title>
    <script src="js/vue.js">script>
    <script src="js/axios.js">script>
head>
<body>
<div id="div">
    {{name}}
    <button @click="send()">发起请求button>
div>
body>
<script>
    new Vue({
        el:"#div",
        data:{
            name: "张三"
        },
        methods:{
            send(){
                //GET方式请求
                // axios.get("testServlet?name=" + this.name)
                //     .then(resp => {
                //         alert(resp.data);
                //     })
                //     .catch(error => {
                //         alert(error);
                //     })
 
                // POST方式请求
                axios.post("testServlet","name="+this.name)
                    .then(resp => {
                        alert(resp.data);
                    })
                    .catch(error => {
                        alert(error);
                    })
            }
        }
    });
script>
html>


import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
 
@WebServlet("/testServlet")
public class TestServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //设置请求和响应的编码
        req.setCharacterEncoding("UTF-8");
        resp.setContentType("text/html;charset=UTF-8");
 
        //获取请求参数
        String name = req.getParameter("name");
        System.out.println(name);
 
        //响应客户端
        resp.getWriter().write("请求成功");
    }
 
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req,resp);
    }
}