ajax封装1

(function (window) {
    function AjaxTool() {
    }

    AjaxTool.ajaxRequest = function (url, paramObj, successCallback, failedCallback) {
        var xhr = new XMLHttpRequest();
        xhr.open('get', url + '?' + getStrWithObject(paramObj), true);
        xhr.send();
        xhr.addEventListener('readystatechange', function (ev2) {
           if(xhr.readyState === 4){
               if(xhr.status === 200){
                   // 请求成功
                   successCallback && successCallback(xhr);
               }else {
                   // 请求失败
                   failedCallback && failedCallback(xhr);
               }
           }
        });
    };


    /*
     {
        name: "张三"，
        age: 18
     }
     [‘name="张三"’， “age=18”, "random=323323232"]
     name="张三"&age=18
   */
    /**
     *  把对象转换成拼接字符串
     * @param {Object}paramObj
     */
    function getStrWithObject(paramObj) {
        var resArr = [];
        // 1. 转化对象
        for (var key in paramObj) {
            var str = key + '=' + paramObj[key];
            resArr.push(str);
        }
        // 2. 拼接时间戳
        resArr.push('random=' + getRandomStr());

        // 3. 数组转成字符串
        return resArr.join('&');
    }

    /**
     * 获取随机时间戳
     * @returns {number}
     */
    function getRandomStr() {
        return Math.random() + (new Date().getTime());
    }

    window.AjaxTool = AjaxTool;
})(window);