AJAX 初学(转)

最新推荐文章于 2025-09-13 15:49:11 发布

转载最新推荐文章于 2025-09-13 15:49:11 发布 · 243 阅读

文章标签：

#ajax #xmlhttprequest #function #javascript #date #xhtml

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这两天一直在埋头苦练AJAX技术，虽然网上对AJAX的看法各有好坏，在我看来AJAX对我来说还是一个很不错的技术，它在很大的程度上减轻了服务器的负担，把一些简单的request通过利用javascript方法创建一个XMLHttpRequest对象发送和接收服务器的信息，不要通过刷新页面就能得到自己想要的效果，这简直是不可思议。下面给出一段AJAX+Servlet+Javascript一段最简单的代码供初学者参考，注意是初学者哦。

<!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Strict //EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Sending Request Data Using GET and POST</title>
<script type="text/javascript">...
var xmlHttp;

function createXMLHttpRequest() ...{
   if(window.ActiveXObject) ...{
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
   } else if(window.XMLHttpRequest) ...{
      xmlHttp = new XMLHttpRequest();
   }
}

function createQueryString() ...{
   var firstName = document.getElementById("firstName").value;
   var middleName = document.getElementById("middleName").value;
   var birthday = document.getElementById("birthday").value;
   var queryString = "firstName = " + firstName + "&middleName=" + middleName + "&birthday=" + birthday;
   return queryString;
}

function doRequestUsingGET() ...{
   createXMLHttpRequest();
   var queryString = "GetAndPostExample?";
   queryString = queryString + createQueryString()
           + "&timeStamp=" + new Date().getTime();
   xmlHttp.onreadystatechange = handleStateChange;
   xmlHttp.open("GET", queryString, true);
   xmlHttp.send(null);
}

function doRequestUsingPOST() ...{
   createXMLHttpRequest();
   var queryString = "GetAndPostExample?";
   queryString = queryString + createQueryString()
           + "&timeStamp=" + new Date().getTime();
   xmlHttp.onreadystatechange = handleStateChange;
   xmlHttp.open("GET", queryString, true);
   xmlHttp.send(null);
}

function doRequestUsingPOST() ...{
   createXMLHttpRequest();
   var url = "GetAndPostExample?timeStamp=" + new Date().getTime();
   var queryString = createQueryString();

xmlHttp.open("POST", url, true);
xmlHttp.onreadystatechange = handleStateChange;