class Ajax {

    constructor() {
        this.ajax = new XMLHttpRequest

    }

    //Promise方法
    get(params) {
        return new Promise((success, error) => {
            var str = ""
            for (const key in params.data) {
                //console.log("key: ", key);
                str += `&${key}=${params.data[key]}`
            }
            str = str.replace("&", "?")
            console.log(`${params.url}${str}`);
            this.ajax.open("GET", `${params.url}${str}`)
            this.ajax.send();
            this.readystatechange(success, error)
        })

    }

    post() { }

    readystatechange(success, error) {
        this.ajax.onreadystatechange = () => {
            if (this.ajax.readyState == 4) {
                if (this.ajax.status == 200) {
                    var data = JSON.parse(this.ajax.responseText)
                    //console.log(data);
                    success(data)
                } else {
                    error(this.ajax)
                }


            }
        }
    }
}

var ajax = new Ajax()