XMLHttpRequestUtil

    //XMLHttpRequest类
        function XMLHTTPRequestUtil() {
            this.Instance = null;
            this.GetXMLHttpRequest = function () {
                var r = window.XMLHttpRequest ? new XMLHttpRequest() : window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : new XMLHttpRequest();
                this.Instance = r;
                return r;
            };
    
            this.AjaxRequest = function (callback, urlParam, method, url) {
      
                //创建XmlHttpRequest对象
                var xmlHttpRequest = this.Instance;
                if (xmlHttpRequest != null) {

                    //建立POST链接
                    xmlHttpRequest.open(method, url, true);
                    xmlHttpRequest.onreadystatechange = callback;
                    //设置请求头
                    xmlHttpRequest.setRequestHeader("Accept", "application/json");
                    xmlHttpRequest.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
                    //发送请求
                    xmlHttpRequest.send(urlParam);
                    
                }
            }
        }