原生ajax类

/*
@desc ajax请求类
@author lee [<complet@163.com>]
@param data object
{
data        # 发送到后台的数据，支持json和表单
url         # 请求的接口地址
type        # 请求方式 get或post
async       # 同步或异步 true:异步 false:同步
json        # 发送的数据是否是json还是表单 true:json false:表单
auth        # 后台授权验证 默认为空
}
*/
function ajax(){
this.xhr
this.data
this.init = function(){
    if(window.XMLHttpRequest){
        this.xhr=new XMLHttpRequest()
    }else{
        this.xhr=new ActiveXObject("Microsoft.XMLHTTP")
    }
    return this
}
this.before = function(func){
    this.xhr.addEventListener(‘readystatechange‘,function(){
        if(this.readyState < 4){
            func()
        }
    })
    return this
}
this.success = function(func){
    this.xhr.addEventListener(‘readystatechange‘,function(){
        if (this.readyState == 4 && this.status == 200){
            var res
            if(this.getResponseHeader(‘content-type‘)===‘application/json‘){
                res = JSON.parse(this.responseText)
            }else{
                res = this.responseText
            }
            func(res)
        }
    })
    return this
}
this.error = function(func){
    this.xhr.addEventListener(‘readystatechange‘,function(){
        if(this.readyState == 4 && this.status != 200){
            func()
        }
    })
    return this
}
this.request = function(obj){
    this.data = obj.data
    var url = obj.url
    var type = obj.type
    var async = obj.async
    var json = (obj.json===true)?true:false
    var auth = obj.auth
    this.init()
    this.xhr.open(type,url,async)
    if(json){
        this.xhr.setRequestHeader("Content-type", "application/json")
        this.data = JSON.stringify(this.data)
    }else{
        this.xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded")
    }
    if(auth){
        this.xhr.withCredentials = true
        this.xhr.setRequestHeader("Authorization", "Basic " + btoa(auth))
    }
    return this
}
this.send = function(){
    this.xhr.send(this.data)
}
}

var xhr = new ajax()
var data = {
data:‘name=lee‘,
url:‘http://localhost/test.php‘,
type:‘post‘,
async:true,
json:false
}
xhr.request(data).before(function(){
console.log(1)
}).success(function(data){
console.log(data)
}).error(function(){
console.log(2)
}).send()