js取服务器端时间，并提供动态下载链接
最近项目中有这样一个需求：
页面动态刷新获取数据库中符合条件的数据的下载链接状态：如果已有可下载链接，就显示链接供用户下载，并显示服务器端当前时间；没有就继续动态获取。
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实现功能：
js取服务器端时间，并动态检索下载链接，显示到页面供用户下载。
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<script language="javascript">var xmlhttp = null;var interval = null;var timeTimeout = null;var statusValue = "";var rtnData = new Array();var btype;var divContent = "";/*** 时间对象的格式化;*/Date.prototype.format = function(format){ /* * eg:format="yyyy-MM-dd hh:mm:ss"; */ var o = { "M+" : this.getMonth()+1, //month "d+" : this.getDate(), //day "h+" : this.getHours(), //hour "m+" : this.getMinutes(), //minute "s+" : this.getSeconds(), //second "q+" : Math.floor((this.getMonth()+3)/3), //quarter "S" : this.getMilliseconds() //millisecond } if(/(y+)/.test(format)) { format = format.replace(RegExp.$1, (this.getFullYear()+"").substr(4 - RegExp.$1.length)); } for(var k in o) { if(new RegExp("("+ k +")").test(format)) { format = format.replace(RegExp.$1, RegExp.$1.length==1 ? o[k] : ("00"+ o[k]).substr((""+ o[k]).length)); } } return format;}function getFile(downUrl){//alert('** downUrl = <%=path%>/jsp/DataRequest/downloadFile.jsp?downUrl='+ downUrl);window.open("<%=path%>/jsp/DataRequest/downloadFile.jsp?downUrl="+ downUrl);}function getOs(){ var OsObject = ""; if(navigator.userAgent.indexOf("MSIE")>0) {return "MSIE"; //IE浏览器} if(isFirefox=navigator.userAgent.indexOf("Firefox")>0){ return "Firefox"; //Firefox浏览器} if(isSafari=navigator.userAgent.indexOf("Safari")>0) { return "Safari"; //Safan浏览器} if(isCamino=navigator.userAgent.indexOf("Camino")>0){ return "Camino"; //Camino浏览器} if(isMozilla=navigator.userAgent.indexOf("Gecko/")>0){ return "Gecko"; //Gecko浏览器}}//页面动态调用该函数，动态获取DB中下载链接function loadXMLDoc(xmlName,dataTypeId){ var ivkUrl = "<%=path%>/jsp/DataRequest/autoFindRtnDataGTS.jsp?xmlName=" + xmlName + "&"+ Math.random(); //alert("** ivkUrl = "+ ivkUrl); if (window.XMLHttpRequest){ xmlhttp=new XMLHttpRequest(); }else if (window.ActiveXObject){ xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } if (xmlhttp){ xmlhttp.open("GET",ivkUrl,false); btype = getOs(); if(btype != "Firefox"){ xmlhttp.onreadystatechange = state_Change; } xmlhttp.send(null); if(btype == "Firefox"){ updatePageGTS();} }else{ alert("Your browser does not support XMLHTTP"); } interval = window.setTimeout("loadXMLDoc('<%=xmlName%>','<%=dataTypeId%>')", 10000); //alert("** interval = "+ interval); //0: 等待；2：数据超大；3：无数据；99：数据获取成功if(statusValue < 0){window.clearTimeout(interval);}else if(statusValue == 2){window.clearTimeout(interval);}else if(statusValue == 3){window.clearTimeout(interval);}else if(statusValue == 99){window.clearTimeout(interval);} } function state_Change(){var dataTypeId = "<%=dataTypeId%>"; if (xmlhttp.readyState==4){if (xmlhttp.status==200){updatePageGTS();}else{//alert("Problem retrieving XML data");}}}//动态获取下载状态及下载链接地址function updatePageGTS(){//alert('updatePageGTS()');rtnData = eval(xmlhttp.responseText);//获取服务端返回数据(下载链接)if(rtnData[0]){statusValue = rtnData[0].reqStatus;if(statusValue < 0){document.getElementById("statusGTS").innerHTML = "<strong>Exception</strong>";}else if(statusValue == 0){document.getElementById("statusGTS").innerHTML = "<strong>Being processed</strong>";}else if(statusValue == 1){document.getElementById("statusGTS").innerHTML = "<strong>Begin zip</strong>";}else if(statusValue == 2){document.getElementById("statusGTS").innerHTML = "<strong>The data you requested is too large</strong>";}else if(statusValue == 3){document.getElementById("statusGTS").innerHTML = "<strong>There is no data</strong>";}else if(statusValue == 99){document.getElementById("statusGTS").innerHTML = "<strong>The request is processed successfully</strong>";}else if(statusValue == 100){document.getElementById("statusGTS").innerHTML = "<strong>Being Zipping</strong>";}else if(statusValue == -99){document.getElementById("reqStatus").innerHTML = "<strong>Being Zipping</strong>";//document.getElementById("reqStatus").innerHTML = "<strong>Zip Error</strong>";}}for(i = 0; i < rtnData.length; i++){if(rtnData[i].downUrl){divContent += '<input id="downloadUrl'+ i +'" type="hidden" name="downloadUrl'+ i +'" value="'+ rtnData[i].downUrl +'" >';//alert("** divContent = "+ divContent);}}document.getElementById("downUrlHidden").innerHTML = divContent;document.getElementById("downloadUrlSize").value = rtnData.length;//alert("** downUrlHidden = "+document.getElementById("downUrlHidden").innerHTML);//alert("** 下载文件数 = "+ rtnData.length);if(rtnData.length == 1 && rtnData[0].downUrl){//1个下载链接rtnData[0].downUrl = '\''+ rtnData[0].downUrl +'\'';//alert("下载链接: "+ rtnData[0].downUrl);document.getElementById("downloadUrlGTS").innerHTML = '<a href="#" onclick="getFile('+ rtnData[0].downUrl +')"><legend>Download results</legend></a>';}if(rtnData.length > 1){//多个下载链接//alert("** 下载连接数:"+ rtnData.length);document.getElementById("downloadUrlGTS").innerHTML = '<a href="#" onclick="submitForm()"><legend>Download results</legend></a>';}} function submitForm(){document.mainform.action= "<%=path%>/jsp/DataRequest/downList.jsp";document.mainform.submit();return true;}//获取服务器端时间,计算和客户端时间差，并在客户端显示function showtime(){var str = '<%=serverTime%>';vararr = str.split(" ");var arr1 = arr[0].split("-");vararr2 = arr[1].split(":");var cTime = new Date().format("yyyy-MM-dd hh:mm:ss");varcArr = cTime.split(" ");var cArr1 = cArr[0].split("-");varcArr2 = cArr[1].split(":");//alert('服务端时间：<%=serverTime%>');//alert('客户端时间：'+ cTime);var serverTimes = new Date(arr1[0], arr1[1], arr1[2], arr2[0], arr2[1], arr2[2]);var clientTimes = new Date(cArr1[0], cArr1[1], cArr1[2], cArr2[0], cArr2[1], cArr2[2]);//alert("** arr2[0]: "+ arr2[0] +"| arr2[1]: "+arr2[1] +"| arr2[2]: "+ arr2[2]);//alert("** cArr2[0]: "+ cArr2[0] +"| cArr2[1]: "+cArr2[1] +"| cArr2[2]: "+ cArr2[2]);var diff = (clientTimes.valueOf() - serverTimes.valueOf());var diffMillions = parseInt(diff,10);//alert("时间差: "+ diffMillions);var currdate = new Date();currdate.setTime(currdate.getTime() - diffMillions);cTime = currdate.format("yyyy-MM-dd hh:mm:ss");//alert('time1 = ' + document.getElementById('time1'));document.getElementById('time1').innerHTML = cTime;//alert('time2 = ' + document.getElementById('time2'));document.getElementById('time2').innerHTML = cTime;timeTimeout = window.setTimeout("showtime();", 1000); //设定函数自动执行时间为 1000 ms(1 s)if(statusValue == 2){window.clearTimeout(timeTimeout);}else if(statusValue == 3){window.clearTimeout(timeTimeout);}if(statusValue == 99 && divContent){//获取到下载链接window.clearTimeout(timeTimeout);}} </script>//触发动态刷新<script language="javascript">showtime();</script><script language="javascript">loadXMLDoc('<%=xmlName%>','<%=dataTypeId%>');</script>?