Ajax技术应用广泛，这种异步加载技术，无需刷新网页即可更新网站内容，全局或者局部均可，所以大家应该学会这种技巧，把技术用上来。
创建demo.json文件，用来做数据源：
{
????"title":"Segmentfault",
????"url":"https://segmentfault.com"
}创建index.html文件，前端页面并加载数据
<!DOCTYPE html>
<html>
<head>
????<meta charset="utf-8">
????<title>jQuery - Ajax - Json</title>
????<script src="http://code.jquery.com/jquery-3.3.1.min.js"></script>
????<script>
????????$(function(){
????????????$("button").click(function(){
????????????????$.ajax({
????????????????????type:"GET",
????????????????????url:"demo.json",
????????????????????dataType:"json",
????????????????????success:function(data){
????????????????????????$("#title").text(data.title);
????????????????????????$("#url").text(data.url);
????????????????????}
????????????????})
????????????})
????????})
????</script>
</head>
<body>
????<button name="button" type="button">加载数据</button>
????<h2>title:<span id="title"></span></h2>
????<h2>url:<span id="url"></span></h2>
</body>
</html>页面中需要引入jQuery库
视频教程：https://pan.baidu.com/s/1vpfT...
