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🌹简述Ajax

Ajax（Asynchronous JavaScript and XML）是一种网页开发技术，通过使用 JavaScript 和 XML（现在更常用的是 JSON）实现在不重新加载整个页面的情况下更新部分页面内容的功能。相比传统的同步请求方式，Ajax 可以异步地向服务器发送请求并接收响应，使得用户可以在无需等待页面全部加载完成的情况下获取该页面部分数据的更新。

⭐作用

实时更新：通过 Ajax 技术，网页可以在不刷新整个页面的情况下，动态地更新部分内容，如加载新的数据、评论、消息等。这种实时更新可以大大提高用户体验，减少用户等待时间。
表单验证：使用 Ajax 技术可以实现表单的即时验证，当用户填写完表单的某一项内容后，可以立即向服务器发送请求进行验证，而不需要等待整个表单提交后才得到反馈。
动态加载：当需要动态加载内容时，比如在网页滚动到底部时自动加载更多内容，或者通过搜索框输入关键词后自动展示相关内容，都可以通过 Ajax 技术实现。
提升响应速度：由于 Ajax 可以异步请求数据，因此网页可以在后台获取数据的同时继续响应用户的操作，提升了网页的响应速度。

🎄异步请求&&同步请求

讲解Ajax和axios相关知识,Vue,ajax,前端

⭐同步

简而言之，同步就是我们点击某个超链接之类的操作

⭐异步

我们在浏览器输入的时候，比如我们输入Java，下面就会自动出来一些关于Java的词条，但是现在浏览器没有刷新，这就是异步操作
讲解Ajax和axios相关知识,Vue,ajax,前端

🎆原生Ajax(复杂，不建议使用，可以帮助理解)

讲解Ajax和axios相关知识,Vue,ajax,前端

原生Ajax
首先我们要准备一个数据地址http://yapi.smart-xwork.cn/mock/169327/emp/list，然后写入下面的代码

讲解Ajax和axios相关知识,Vue,ajax,前端
但是我们发现这种方法太复杂了，不利于我们开发使用
下面我们介绍一种简单的方法，axios

🛸axios

axios就是对原生的Ajax进行了封装，简化书写

官网https://www.axios-http.cn/

Axios 主要有以下特点：

基于 Promise 实现： Axios 提供的 API 返回的是 Promise 对象，使得异步请求更加方便和可读。

支持拦截器：支持请求和响应拦截器，可以在请求被发送或响应被接收之前对其进行拦截和修改，可用于设置公共请求头、loading 状态提示、错误处理等。

支持并发请求：可以一次性发起多个请求，并且在所有请求完成后返回结果。

自动转换数据类型：Axios 能够根据响应数据类型自动转换为 JSON 对象。

支持取消请求：Axios 支持取消请求，可以在请求未完成时中断请求。

🎍axios入门

讲解Ajax和axios相关知识,Vue,ajax,前端

🎈代码实现

首先引入js文件
讲解Ajax和axios相关知识,Vue,ajax,前端

/* axios v0.18.0 | (c) 2018 by Matt Zabriskie */
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 * @license  MIT
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o=n(23);r.prototype.throwIfRequested=function(){if(this.reason)throw this.reason},r.source=function(){var e,t=new r(function(t){e=t});return{token:t,cancel:e}},e.exports=r},function(e,t){"use strict";e.exports=function(e){return function(t){return e.apply(null,t)}}}])});
//# sourceMappingURL=axios.min.map

下面编写代码

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="js/axios-0.18.0.js"></script>
</head>
<body>
  <input type="button" value="获取数据get" onclick="get()">

  <input type="button" value="删除数据post" onclick="post()">
</body>
<script>
  function get(){
    //通过axios发送异步请求-get
    axios({
      methods:"get",
      url:"http://yapi.smart-xwork.cn/mock/169327/emp/list"
    }).then(result=>{
      console.log(result.data)
    })

  }
  function post(){
    //通过axios发送异步请求-post
    axios({
      method:"post",
      url:"http://yapi.smart-xwork.cn/mock/169327/emp/deleteById",
      data:"id=1"
    }).then(result=>{
      console.log(result.data)
    })
  }
</script>
</html>