//创建 httpRequest 对象

//显示平台系统时间

getSystemTime.jsp //获得系统的当前时间，也就是输出结果的页面 <%@ page language="java" %> <%@ page contentType="text/html;charset=GB2312" %> <%@ page import="java.util.Date"%> <%@ page import="java.sql.Timestamp"%> <%@ page import="java.io.IOException"%> <% Date d = new Date(); Timestamp ts = new Timestamp(d.getTime()); String result = ts.toString().substring(0,16); out.write(result,0,result.length()); %> ajax.js function makeRequest(url) { http_request = false; if (window.XMLHttpRequest) { http_request = new XMLHttpRequest(); if (http_request.overrideMimeType){ http_request.overrideMimeType('text/xml'); } } else if (window.ActiveXObject) { try{ 

http_request = new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { try { http_request = new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) { } } } if (!http_request) { alert("您的浏览器不支持当前操作，请使用 IE 5.0 以上版本!"); return false; } //定义页面调用的方法 init,不是 init();没有(); http_request.onreadystatechange = init; http_request.open('GET', url, true); //禁止 IE 缓存 http_request.setRequestHeader("If-Modified-Since","0"); //发送数据 http_request.send(null); //每 60 秒刷新一次页面 setTimeout("makeRequest('"+url+"')", 60000); } function init() { if (http_request.readyState == 4) { if (http_request.status == 0 || http_request.status == 200) { var result = http_request.responseText; if(result==""){ result = "系统时间获取失败"; } document.getElementById ("sysTimeShow").innerHTML="平台系统时间："+result; } else {//http_request.status != 200 alert("请求失败!"); } } }