class Ajax {

    //请求方式不一样
    //请求参数不一样
    //请求地址不一样
    constructor() {

        this.ajax = new XMLHttpRequest()
    }



    get(params) {
        var str = ""
        for (const key in params.data) {

            str += `&${key}=${params.data[key]}`

        }
        str = str.replace("&", "?")
        this.ajax.open("GET", params.url + str)
        this.ajax.send();
        this.statechange(params)
    }


    post() {

        this.open("POST", "http://127.0.0.1/index.php")
    }

    statechange (params) {
        this.ajax.onreadystatechange = () => {
            if (this.ajax.readyState == 4) {
                if (this.ajax.status == 200) {
                    var data = JSON.parse(this.ajax.responseText)
                    switch (data.status) {
                        case 200:
                            params.success(data.result)
                            break;
                        case 404:
                            alert(data.msg)
                            throw new Error(data.msg)
                            break;
                    
                    }
                    // 
                } else {
                    params.error(this.ajax)
                }
            }
        }
    }







}




var ajax = new Ajax()