ajax实例

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一个简单的AJAX实例

创建一个简单的XMLHttpRequest，从一个TXT文件中返回数据。

<html><!DOCTYPE html><html><head><script>function loadXMLDoc(){var xmlhttp;if (window.XMLHttpRequest)  {// code for IE7+, Firefox, Chrome, Opera, Safari  xmlhttp=new XMLHttpRequest();  }else  {// code for IE6, IE5  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");  }xmlhttp.onreadystatechange=function()  {  if (xmlhttp.readyState==4 && xmlhttp.status==200)    {    document.getElementById("myDiv").innerHTML=xmlhttp.responseText;    }  }xmlhttp.open("GET","/try/ajax/ajax_info.txt",true);xmlhttp.send();}</script></head><body><div id="myDiv"><h2>使用 AJAX 修改该文本内容</h2></div><button type="button" onclick="loadXMLDoc()">修改内容</button></body></html>

用AJAX加载 XML 文件

创建一个简单的XMLHttpRequest，从一个XML文件中返回数据。

<html><!DOCTYPE html><html><head><script>function loadXMLDoc(url){var xmlhttp;if (window.XMLHttpRequest)  {// code for IE7+, Firefox, Chrome, Opera, Safari  xmlhttp=new XMLHttpRequest();  }else  {// code for IE6, IE5  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");  }xmlhttp.onreadystatechange=function()  {  if (xmlhttp.readyState==4 && xmlhttp.status==200)    {    document.getElementById('A1').innerHTML=xmlhttp.status;    document.getElementById('A2').innerHTML=xmlhttp.statusText;    document.getElementById('A3').innerHTML=xmlhttp.responseText;    }  }xmlhttp.open("GET",url,true);xmlhttp.send();}</script></head><body><h2>Retrieve data from XML file</h2><p><b>Status:</b><span id="A1"></span></p><p><b>Status text:</b><span id="A2"></span></p><p><b>Response:</b><span id="A3"></span></p><button onclick="loadXMLDoc('note.xml')">Get XML data</button></body></html>

用AJAX进行一次 HEAD 请求

检索资源（文件）的头信息。

<html><!DOCTYPE html><html><head><script>function loadXMLDoc(url){var xmlhttp;if (window.XMLHttpRequest)  {// code for IE7+, Firefox, Chrome, Opera, Safari  xmlhttp=new XMLHttpRequest();  }else  {// code for IE6, IE5  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");  }xmlhttp.onreadystatechange=function()  {  if (xmlhttp.readyState==4 && xmlhttp.status==200)    {    document.getElementById('p1').innerHTML=xmlhttp.getAllResponseHeaders();    }  }xmlhttp.open("GET",url,true);xmlhttp.send();}</script></head><body><p id="p1">The getAllResponseHeaders() function returns the header information of a resource, like length, server-type, content-type, last-modified, etc.</p><button onclick="loadXMLDoc('/try/ajax/ajax_info.txt')">Get header information</button></body></html>

用AJAX进行一次指定的 HEAD 请求

检索资源（文件）的指定头信息。

<html><!DOCTYPE html><html><head><script>function loadXMLDoc(url){var xmlhttp;if (window.XMLHttpRequest)  {// code for IE7+, Firefox, Chrome, Opera, Safari  xmlhttp=new XMLHttpRequest();  }else  {// code for IE6, IE5  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");  }xmlhttp.onreadystatechange=function()  {  if (xmlhttp.readyState==4 && xmlhttp.status==200)    {    document.getElementById('p1').innerHTML="Last modified: " + xmlhttp.getResponseHeader('Last-Modified');    }  }xmlhttp.open("GET",url,true);xmlhttp.send();}</script></head><body><p id="p1">The getResponseHeader() function is used to return specific header information from a resource, like length, server-type, content-type, last-modified, etc.</p><button onclick="loadXMLDoc('/try/ajax/ajax_info.txt')">Get "Last-Modified" information</button></body></html>

用AJAX从数据库返回数据

用AJAX网页如何获取数据库中的信息

<html><!DOCTYPE html><html><head><script>function showCustomer(str){var xmlhttp;    if (str=="")  {  document.getElementById("txtHint").innerHTML="";  return;  }if (window.XMLHttpRequest)  {// code for IE7+, Firefox, Chrome, Opera, Safari  xmlhttp=new XMLHttpRequest();  }else  {// code for IE6, IE5  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");  }xmlhttp.onreadystatechange=function()  {  if (xmlhttp.readyState==4 && xmlhttp.status==200)    {    document.getElementById("txtHint").innerHTML=xmlhttp.responseText;    }  }xmlhttp.open("GET","/try/ajax/getcustomer.php?q="+str,true);xmlhttp.send();}</script></head><body><form action=""> <select name="customers" onchange="showCustomer(this.value)" style="font-family:Verdana, Arial, Helvetica, sans-serif;"><option value="APPLE">Apple Computer, Inc.</option><option value="BAIDU ">BAIDU, Inc</option><option value="Canon">Canon USA, Inc.</option><option value="Google">Google, Inc.</option><option value="Nokia">Nokia Corporation</option><option value="SONY">Sony Corporation of America</option></select></form><br><div id="txtHint">Customer info will be listed here...</div></body></html>

用AJAX从XML 文件返回数据

创建一个XMLHttpRequest从XML文件中检索数据并显示在一个HTML表格中。

<html><!DOCTYPE html><html><head><script>function loadXMLDoc(url){var xmlhttp;var txt,x,xx,i;if (window.XMLHttpRequest)  {// code for IE7+, Firefox, Chrome, Opera, Safari  xmlhttp=new XMLHttpRequest();  }else  {// code for IE6, IE5  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");  }xmlhttp.onreadystatechange=function()  {  if (xmlhttp.readyState==4 && xmlhttp.status==200)    {    txt="<table border='1'><tr><th>Title</th><th>Artist</th></tr>";    x=xmlhttp.responseXML.documentElement.getElementsByTagName("CD");    for (i=0;i<x.length;i++)      {      txt=txt + "<tr>";      xx=x[i].getElementsByTagName("TITLE");        {        try          {          txt=txt + "<td>" + xx[0].firstChild.nodeValue + "</td>";          }        catch (er)          {          txt=txt + "<td> </td>";          }        }      xx=x[i].getElementsByTagName("ARTIST");        {        try          {          txt=txt + "<td>" + xx[0].firstChild.nodeValue + "</td>";          }        catch (er)          {          txt=txt + "<td> </td>";          }        }      txt=txt + "</tr>";      }    txt=txt + "</table>";    document.getElementById('txtCDInfo').innerHTML=txt;    }  }xmlhttp.open("GET",url,true);xmlhttp.send();}</script></head><body><div id="txtCDInfo"><button onclick="loadXMLDoc('cd_catalog.xml')">Get CD info</button></div></body></html>

用callback函数的AJAX实例

用一个callback函数创建一个XMLHttpRequest，并从一个TXT文件中检索数据。

<!DOCTYPE html><html><head><script>var xmlhttp;function loadXMLDoc(url,cfunc){if (window.XMLHttpRequest)  {// IE7+, Firefox, Chrome, Opera, Safari 代码  xmlhttp=new XMLHttpRequest();  }else  {// IE6, IE5 代码  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");  }xmlhttp.onreadystatechange=cfunc;xmlhttp.open("GET",url,true);xmlhttp.send();}function myFunction(){loadXMLDoc("/try/ajax/ajax_info.txt",function()  {  if (xmlhttp.readyState==4 && xmlhttp.status==200)    {    document.getElementById("myDiv").innerHTML=xmlhttp.responseText;    }  });}</script></head><body><div id="myDiv"><h2>使用 AJAX 修改文本内容</h2></div><button type="button" onclick="myFunction()">修改内容</button></body></html>

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