Ajax之get、post实例(最原始的XMLHttpServlet)

发布时间：2020-12-16 02:10:22 所属栏目：百科来源：网络整理

导读：2014年12月23日15:36:10 天气阴心情极度低落 ajaxGet2014122301.jsp %@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/

2014年12月23日15:36:10 天气阴心情极度低落

ajaxGet2014122301.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
	
	window.onload = function() {
		
		//1.获取a节点,并为其添加onclick响应函数
		document.getElementsByTagName("a")[0].onclick = function() {
			
			//3.创建一个XMLHttpRequest对象
			var request = new XMLHttpRequest();
			
			//4.准备发送请求的数据： url
			var url= this.href + "?time = " + new Date();
			var method = "GET";
			
			//5.调用XMLHttpRequest 对象的open方法
			request.open(method,url);
			
			///6.调用XMLHttpRequest 对象的send方法
			request.send(null);
			
			//7.为XMLHttpRequest对象添加onreadystatechange响应函数			
			request.onreadystatechange = function() {
				//8.判断响应是否完成：XMLHttpRequest对象的readyState 属性为4的时候
				if (request.readyState == 4) {
					//9.再判断响应是否可用：XMLHttpRequest 对象的 status 为200
					if (request.status == 200 || request.status == 304) {
						//10.打印响应结果：responseText;
						alert(request.responseText);
					}
				}
			}
			//2.取消a节点的默认行为
			return false;
		}
	}
</script>
</head>
<body>
	<a href="HelloAjax.txt">helloAjax2014122301</a>
</body>
</html>

ajaxPost2014122301.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
	
	window.onload = function() {
		document.getElementsByTagName("a")[0].onclick = function() {
			var request = new XMLHttpRequest();
			var url= this.href + "?time = " + new Date();
			var method = "POST";
			request.open(method,url);
			
			request.setRequestHeader("ContentType","application/x-www=form-urlencoded")
			request.send("name='atguigu'");
			request.onreadystatechange = function() {
				if (request.readyState == 4) {
					if (request.status == 200 || request.status == 304) {
						alert(request.responseText);
					}
				}
			}
			return false;
		}
	}
</script>
</head>
<body>
	<a href="HelloAjax.txt">helloAjax2014122301</a>
</body>
</html>

需要注意的地方是对于post请求必须执行完request.setRequestHeader("ContentType","application/x-www=form-urlencoded")而后再执行request.send("name='atguigu'");，否则异步提交不起作用。

（编辑：李大同）

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