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<script type="text/javascript">

        //定義XmlhttpRequest對(duì)象

        var xmlrequest;

        //完成對(duì)對(duì)象XmlHttpRequest對(duì)象的初始化

        function createXmlHttpRequest(){

            if(window.XMLHttpRequest){

                //DOM 2瀏覽器

                xmlrequest = new XMLHttpRequest();

            }else if(window.ActiveXObject){

                //IE 瀏覽器

                try{

                    xmlrequest = new ActiveXOPbject("Msxml2.XMLHTTP");

                }catch(e){

                    try{

                        xmlrequest = new ActiveXObject("Microsoft.XMlHTTP");

                    }catch(e){

                    }                   

                }

            }

        }

        //事件處理函數(shù)，當(dāng)下拉列表選擇改變時(shí)，觸發(fā)改事件

        function change(id){

            //初始化XMLHttpRequest對(duì)象

            createXmlHttpRequest();

            //設(shè)置請(qǐng)求響應(yīng)的URL

            var url = "second.jsp?id="+id;

            //打開(kāi)與服務(wù)器響應(yīng)地址的連接xmlrequest.open(method,url,async,user,password)

            xmlrequest.open("POST",url,true);

            //設(shè)置請(qǐng)求頭(Post必須設(shè)置，GET方式不需要)

            xmlrequest.setRequestHeader("Context-Type","application/x-www-form-urlencoded");

            //設(shè)置處理響應(yīng)的回調(diào)函數(shù)，此函數(shù)processResponse是自己定義的

            xmlrequest.onreadystatechange = processResponse;

            //發(fā)送請(qǐng)求

            xmlrequest.send(null);

        }

        //定義處理響應(yīng)的回調(diào)函數(shù)

        function processResponse(){

            //響應(yīng)完成且響應(yīng)正常

            if(xmlrequest.readyState == 4){

                if(xmlrequest.status == 200){

                    //信息已經(jīng)成功返回，開(kāi)始處理信息

                    var headers = xmlrequest.getAllResponseHeaders();

                    //通過(guò)警告框輸出相應(yīng)頭

                    alert("相應(yīng)頭的類型 "+ typeof headers + "\n" + headers);

                    //在頁(yè)面輸出所有的相應(yīng)頭

                    document.getElementById("output").innerHTML = headers;

                }else{

                    //頁(yè)面不正常

                    window.alert("您所請(qǐng)求的頁(yè)面異常。");

                }

            }

        }

    </script>