淺談jQuery非同步物件（XMLHttpRequest）_javascript技巧

 //1.00建立非同步物件
            var xhr = new XMLHttpRequest();
            //2.0
            xhr.open("post", url,params, true);
            //3.0將參數使用Formdata屬性傳遞
            xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
            //4.0設定回呼函數
            xhr.onreadystatechange = function () {
                if (xhr.readyState == 4 && xhr.status == 200) {
                    alert(xhr.responseText);
                }
            }
            //5.0傳遞參數
            xhr.send(params);

 xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");

var ajaxHelp = {
    CreateXHR: 函數 () {
        //建立物件
        var xhr = new XMLHttpRequest();
        返回 xhr;
    },
    //ajax的get請求
    AjaxGet: 函數 (url, 回呼) {
        this.AJaxCommon("get", url, null, callBack);
    },
    //ajax的post請求
    AjaxPost：函數（url、參數、callBack）{
        this.AJaxCommon("post", url, params, callBack);
    },
    AJaxCommon：函數（方法、url、參數、回呼）{
        //1.0
        var xhr = this.CreatXHR();
        //2.0
        xhr.open(方法, url, true);
        //3.0
        if (方法==「取得」) {
            xhr.setRequestHeader("If-Modified-Since", "0");
        } 其他 {
            xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        }
        //4.0
        xhr.onreadystatechange = function () {
            if (xhr.readyState == 4 && xhr.status == 200) {
                var datas = JSON.parse(xhr.responseText);
                //執行回呼函數
                回調(資料);
            }
        }
        //5.0
        xhr.send(params);
    }
};