[Javascript]用于发送异步请求的类

        /// <summary>
        /// 用于发送异步请求
        /// </summary>
        /// <param name="sUrl">发送请求的URL</param>
        /// <param name="sMethod">请求方式"post"/"get"</param>
        /// <param name="sPostdata">要发生地Xml字符串</param>
        /// <param name="fPostback">回调函数,形如:function(xmldoc){}</param>
        function xmlhttp(sUrl,sMethod,sPostdata,fPostback)
        {
        ///静态方法***************************************************
        
            /// <summary>
            /// 通过Xml字符串获取XmlDoc对象
            /// </summary>
            /// <param name="txt">Xml字符串</param>
            /// <returns>XmlDoc对象</returns>
            xmlhttp.loadXMLString = function(txt)
            {
                try
                    { //Internet Explorer
                    xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
                    xmlDoc.async= false;
                    xmlDoc.loadXML(txt);
                    return(xmlDoc);
                }
                catch(e)
                {
                    try
                    {//Firefox,Mozilla,Opera,etc
                        parser = new DomParser();
                        xmlDoc = parser.parseFormString(txt,"text/xml");
                        return(xmlDoc);
                    } 
                    catch(e)
                    {
                        alert(e.message())
                        return(null);
                    }
                }
            }
            
            /// <summary>
            /// xmlHttp.onreadystatechange 事件处理函数
            /// </summary>
            /// <param name="oxmlhttp">指定一个xmlhttp对象用以外部调用</param>
            xmlhttp.Postback = function(oxmlhttp)
            {
                return function()
                {
                    if(oxmlhttp.readyState==4)
                    {
                        if(oxmlhttp.status==200)
                            fPostback(oxmlhttp.responseXML);
                        else
                            alert("error:" + oxmlhttp.status +" "+ oxmlhttp.statusText);
                    }
                }
            }
            
        ///成员***************************************************
 
            ///xmlhttp对象;
            this.oXmlHttp = null;
            
            ///xmlhttp对象初始化
            if(window.ActiveXObject)   //如果是IE浏览器
                this.oXmlHttp = new ActiveXObject("Microsoft.XMLHTTP");//用ActiveXObject来创建xmlHttp对象
            else if (window.XMLHttpRequest) //如果不是IE浏览器
                this.oXmlHttp = new XMLHttpRequest(); //用XMLHttpRequest来创建对象
                this.oXmlHttp.open(sMethod,sUrl,true); //以异步方式打开远程网页
                this.oXmlHttp.setRequestHeader("CONTENT-TYPE","application/x-www-form-urlencoded");//设置HTTP头
                this.oXmlHttp.onreadystatechange = xmlhttp.Postback(this.oXmlHttp);  
            
            ///发送方法
            this.fSend = function()
            {
                this.oXmlHttp.send(xmlhttp.loadXMLString(sPostdata));
            }  
           
        }

 

使用事例：

 

function fPostback(o)
{ 
    alert(o.getElementsByTagName("status")[0].text);
}
        
sPostdata="<a>hehe</a>";
Myxmlhttp = new xmlhttp('bin\\functions.aspx?method=s','post',sPostdata,fPostback);
Myxmlhttp.fSend();
obj=Myxmlhttp.oXmlHttp;