class Ajax {

    // url 接口地址
    // 请求参数
    // 请求方法
    // 请求成功的回调
    // 请求失败的回调

    http = new XMLHttpRequest();
    constructor () {
    }

    //http://127.0.0.1:3000/api/json/index ?id=1&page=2
    get(option) {
        var params = ""
        for (const key in option.data) {
            params+= `&${key}=${option.data[key]}`
        }
        params = params.replace("&", "?")
        option.url = option.url + params

        this.http.open("GET", option.url);
        this.http.send()
        this.onreadystatechange(option)
    }

    post(option) {
      this.http.open("POST", option.url);
      this.http.setRequestHeader('Content-Type', 'application/josn');
      this.http.send(JSON.stringify(option.data))
      this.onreadystatechange(option)
    }


    onreadystatechange(callback) {
        this.http.onreadystatechange = () => {
            if (this.http.readyState == 4) {
              if (this.http.status == 200) {
                callback.success(JSON.parse(this.http.response))
              }  else {
                callback.error(this.http)
              }
            }
          }
    }
}

var ajax = new Ajax()