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Detailed explanation of Ajax and $.ajax examples

php中世界最好的语言
php中世界最好的语言Original
2018-04-24 17:05:481952browse

This time I will bring you a detailed explanation of Ajax and $.ajax examples. What are the precautions when using Ajax and $.ajax. The following is a practical case, let’s take a look.

Example 1 (Basic creation format of Ajax request):

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
 <title>Ajax练习(GET,不考虑浏览器兼容性)</title>
 <script type="text/JavaScript">
  function doRequest() {
   //不考虑浏览器兼容性问题
   var xmlHttp = new XMLHttpRequest();
   //打开一个与Http服务器的连接
   xmlHttp.open("GET", "Default.aspx", true);
   //与服务器端交互
   xmlHttp.send(null);
   //监听服务器端响应状态的改变事件
   xmlHttp.onreadystatechange = function () {
    //客户端与服务器端交互完成
    if (xmlHttp.readyState == 4) {
     //服务器端返回Http状态码:200表示请求成功,404未找到,403错误
     if (xmlHttp.status == 200) {
      //获得服务器端资源
      var result = xmlHttp.responseText;
      alert(result);
     }
    }
   }
  }
 </script>
</head>
<body>
 <form id="form1" runat="server">
 <p>
  <input type="button" id="btn" value="异步请求" onclick="doRequest()" />
 </p>
 </form>
</body>
</html>
<head runat="server">
 <title>AjaxDemo实例</title>
 <script src="JS/jQuery-1.4.1-vsdoc.js" type="text/javascript"></script>
 <script type="text/javascript">
  //使用Ajax读取浏览器的工作内容 
  function readRequest() {
   //不考虑浏览器的兼容性问题
   var xmlhttp = new XMLHttpRequest();
   //打开一个与服务器相关的链接
   //发送请求
   //请求的方式(获取/发送),请求页面,是否异步
   xmlhttp.open("GET", "AjaxDemo.aspx", true);
   //发送数据
   xmlhttp.send(null);
   //接受服务器返回结果
   xmlhttp.onreadystatechange = function() {
    //请求完成
    if (xmlhttp.readyState == 4) {
     //链接成功
     if (xmlhttp.status == 200) {
      //输出浏览器的内容
      var result = xmlhttp.responseText;
      alert(result);
      window.alert("读取浏览器的内容成功!");
     }
    }
   };
  };
  function btn_Click() {
   var http = new ActiveXObject("Microsoft.XMLHTTP");
   //或者使用这一句创建 var xmlhttp = new XMLHttpRequest();
   if (!http) {
    alert("创建xmlhttp对象异常!");
    return false;
   }
   http.open("POST", "AjaxDemo.ashx", false);
   http.onreadystatechange = function() {
    if (http.readyState == 4) {
     //链接成功
     if (http.status == 200) {
      alert(http.responseText);
      document.getElementById("Text1").value = http.responseText;
     } else {
      window.alert("Ajax服务器返回错误!");
     }
    }
   };
   http.send();
  };
 </script>
</head>
<body>
 <form id="form1" runat="server">
 <p>
 <input id="Button1" type="button" value="使用Ajax读取浏览器的内容" onclick="readRequest()" />
 <br/>
  <input id="Text1" type="text" />  
  <input id="Button2" type="button" value="获取当前时间" onclick="btn_Click()"/>
 </p>
 </form>
</body>

Example 2 (see attachment)

Consider browser compatibility for Ajax request processing and obtain background xml file content.

Example 3 (see attachment)

Use $.Ajax to obtain background reading xml file content information.

function readXML1() {
   //创建XML对象
   var xmldom = new ActiveXObject("Microsoft.XMLDOM");
   //设置为异步
   xmldom.async = "false";
   //加载需要读取的XML文档
   xmldom.load("XML1.xml");
   info = "";
   //需要读取的根节点
   var node = xmldom.selectNodes("student");
   //依次读取其中的内容
   info = node[0].childNodes[0].nodeTypedValue + " <br/>" + node[0].childNodes[1].nodeTypedValue+ "<br/>" + node[0].childNodes[2].nodeTypedValue;
   document.getElementById("xmlmsg").innerHTML = info;
  };
 function readXML2() {
   //实例化xml对象
   var xml = new ActiveXObject("Microsoft.XMLDOM");
   //异步设置
   xml.async = "false";
   //加载需要读取的XML文档
   xml.load("XML2.xml");
   info = "";
   //选择需要读取的对象名称
   var fnode = xml.documentElement.selectNodes("people");
   //循环输出文档的内容
   for (var i = 0; i < fnode.length; i++) {
    for (var j = 0; j < fnode[i].childNodes.length; j++) {
     info += fnode[i].childNodes[j].text + "<br/>";
    }
   }
   document.getElementById("xmlmsg").innerHTML = info;
  };

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

Recommended reading:

Summary of the advantages and disadvantages of Ajax

##Detailed explanation of the interaction between Ajax() and the background

Summary of three methods for Ajax to achieve cross-domain access

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