Ajax向服务器发送请求

Ajax get方式向服务器发送请求：

<script type="text/javascript">  
    //创建XMLHttpReques对象  
    function createXMLHttpRequest(){  
          
        if(window.XMLHttpRequest){  
            //Mozilla浏览器  
              
            XMLHttpReq=new XMLHttpRequest();  
        }else{  
              
            //IE浏览器  
            if(window.ActiveXObject){  
                try{  
                    XMLHttpReq=new ActionXObject("Msxm12.XMLHTTP");  
                }catch(e){  
                    try{  
                        XMLHttpReq=new ActiveXObject("Microsoft.XMLHTTP");  
                    }catch(e){}  
                }  
            }  
        }  
    }  
    //处理服务器响应结果  
     function handleResponse() {  
        // 判断对象状态  
        if (XMLHttpReq.readyState == 4) {   
            // 信息已经成功返回，开始处理信息  
           if (XMLHttpReq.status == 200) {   
                var out = "";  
                var res = XMLHttpReq.responseXML;  
                var response= res.getElementsByTagName("response")[0].firstChild.nodeValue;  
                //5. 解析服务器返回的信息,更新用户界面  
                document.getElementById("Hello").innerHTML = response;  
               }  
         }  
       }  
    //发送客户端的请求  
    function sendRequest(url){  
        //1.创建XMLHttpRequest  
        createXMLHttpRequest();  
        //2.设置回调函数  
        XMLHttpReq.onreadystatechange=handleResponse;  
        //3.初始化XMLHttpRequest组建并发送请求  
        XMLHttpReq.open("GET",url,true);  
        //发送请求  
        XMLHttpReq.send(null); 
  //post请求时把GET，改为POST,还要加上
 //XMLHttpReq.setRequestHeader("Content-Type","application/x-www-form-urlencoded;charset=UTF-8");
 //把请求的参数写在XMLHttpReq.send(key=value);中
    }  
    //开始调用Ajax的功能  
    function sayHello()  
    {  
        var name=document.getElementById("name").value;  
        //发送请求  
        sendRequest("SayHell?name="+name);  
    }  
</script>

post方式向服务器发送请求时候要添加上：

var name = document.getElementById("name").value;
XMLHttpReq.setRequestHeader("Content-Type","application/x-www-form-urlencoded;charset=UTF-8");
XMLHttpReq.send("name="+name);

index.jsp页面：

<body>
<input type = "text" name = "name" id = "name" onblur = "sayhello();"/>
<div id = "Hello"></div>
</body>

servlet代码片段：

	public void service(HttpServletRequest request,HttpServletResponse response) throws servletexception,IOException{
		response.setContentType("text/xml;charset=UTF-8");  
        response.setHeader("Cache-Control","no-cache"); 
		String name = request.getParameter("name");
		System.out.println(name);
		 PrintWriter out = response.getWriter();
		 out.println(name);
		 out.close();
	}

原文地址：https://www.jb51.cc/ajax/166020.html

Ajax向服务器发送请求

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