var xhr = new XMLHttpRequest() 
  xhr.open("GET","js/text.js",true) 
  xhr.send()          
  xhr.onreadystatechange = function(){  //
   if(xhr.readyState === 4&& xhr.status === 200){ 
    var data = xhr.responseText 
    var datas = JSON.parse(data) 
    console.log(datas) 
   }
  }
  

  var xhr = new XMLHttpRequest() 
  xhr.open("POST","js/text.js",true) 
  xhr.setRequestHeader("Content-type","application/x-www-form-urlencoded"); 
  xhr.send()         
  xhr.onreadystatechange = function(){  
   if(xhr.readyState === 4&& xhr.status === 200){ 
    var data = xhr.responseText 
    var datas = JSON.parse(data) 
    console.log(datas) 
   }
  }

{
 "name":"小明",
 "age":24,
 "array":[1,51,3,4,4,6,64]
}

   function Ajax(type, url, data, success){
   
   var xhr = null; // 初始化xhr
   if(window.XMLHttpRequest){ //兼容IE
    xhr = new XMLHttpRequest();
   } else {
    xhr = new ActiveXObject('Microsoft.XMLHTTP')
   }
   
   var type = type.toUpperCase();
   
   var random = Math.random(); //创建随机数
   
   if(type == 'GET'){
    if(data){
     xhr.open('GET', url + '"Content-type", "application/x-www-form-urlencoded");
    xhr.send(data);
   }
   
   
   xhr.onreadystatechange = function(){  // 创建监听函数
    if(xhr.readyState == 4&&xhr.status == 200){
      success(xhr.responseText);
     } 
    }
  }
   
  Ajax('get', 'js/text.js', "", function(data){ //调用函数
   console.log(JSON.parse(data));
  });

{
 "name":"小明",
 "age":24,
 "array":[1,51,3,4,4,6,64]
}

$.ajax({
   url:"./js/text.js", 
   type:"GET",  
   dataType:"json", 
   success:function(data){ 
    console.log(data)
   },
   error:function(res){ 
    console.log("请求失败！")
   }
  })

{
 "name":"小明",
 "age":24,
 "array":[1,51,3,4,4,6,64]
}