PHP AJAX RSS

RSS Reader is used to read RSS feeds.

RSS allows for quick browsing of news and updates.

AJAX RSS Reader

In the following example, we will demonstrate a RSS reader, through which content from RSS is loaded without refreshing the web page:

##Example

When the user selects an RSS-feed in the drop-down list above, a function named "showRSS()" will be executed. This function is triggered by the "onchange" event:

<!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="UTF-8">
     <title>PHP中文网(php.cn)</title>
     <script>
         function showRSS(str)
         {
             if (str.length==0)
             {
                 document.getElementById("rssOutput").innerHTML="";
                 return;
             }
             if (window.XMLHttpRequest)
             {
                 // IE7+, Firefox, Chrome, Opera, Safari 浏览器执行代码
                 xmlhttp=new XMLHttpRequest();
             }
             else
             {
                 // IE6, IE5 浏览器执行代码
                 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
             }
             xmlhttp.onreadystatechange=function()
             {
                 if (xmlhttp.readyState==4 && xmlhttp.status==200)
                 {
                     document.getElementById("rssOutput").innerHTML=xmlhttp.responseText;
                 }
             }
             xmlhttp.open("GET","getrss.php?q="+str,true);
             xmlhttp.send();
         }
     </script>
 </head>
 <body>
 
 <form>
     <select onchange="showRSS(this.value)">
         <option value="">选择一个 RSS-feed:</option>
         <option value="rss">读取 RSS 数据</option>
     </select>
 </form>
 <br>
 <div id="rssOutput">RSS-feed 数据列表...</div>
 </body>
 </html>

showRSS() function will perform the following steps:

· Check whether an RSS-feed is selected

· Create an XMLHttpRequest object

· Create a function that executes when the server response is ready

· Send a request to a file on the server

· Please note the parameter (q) added to the end of the URL (including Contents of the drop-down list)

XML file

<?xml version="1.0" encoding="UTF-8" ?>
<rss version="2.0">
    <channel>
        <title>php教程</title>
        <link>http://www.php.cn</link>
        <description>学的不仅技术，更新梦想！！</description>
        <item>
            <title>RSS 教程</title>
            <link>http://www.php.cn/rss/rss-tutorial.html</link>
            <description>通过使用 RSS，您可以浏览与您的工作相关的新闻</description>
        </item>
        <item>
            <title>XML 教程</title>
            <link>http://www.php.cn/xml/xml-tutorial.html</link>
            <description>XML 指可扩展标记语言（eXtensible Markup Language)</description>
        </item>
    </channel>
</rss>

PHP file

The server page called by the above JavaScript is a PHP file named "getrss.php":

<?php
 header("Content-type:text/html;charset=utf-8");    //设置编码
 // rss 文件
 $xml="rss_demo.xml";
 $xmlDoc = new DOMDocument();
 $xmlDoc->load($xml);
 
 // 从 "<channel>" 中读取元素
 $channel=$xmlDoc->getElementsByTagName('channel')->item(0);
 $channel_title = $channel->getElementsByTagName('title')
     ->item(0)->childNodes->item(0)->nodeValue;
 $channel_link = $channel->getElementsByTagName('link')
     ->item(0)->childNodes->item(0)->nodeValue;
 $channel_desc = $channel->getElementsByTagName('description')
     ->item(0)->childNodes->item(0)->nodeValue;
 
 // 输出 "<channel>" 中的元素
 echo("<p><a href='" . $channel_link
     . "'>" . $channel_title . "</a>");
 echo("<br>");
 echo($channel_desc . "</p>");
 
 // 输出 "<item>" 中的元素
 $x=$xmlDoc->getElementsByTagName('item');
 for ($i=0; $i<=1; $i++) {
     $item_title=$x->item($i)->getElementsByTagName('title')
         ->item(0)->childNodes->item(0)->nodeValue;
     $item_link=$x->item($i)->getElementsByTagName('link')
         ->item(0)->childNodes->item(0)->nodeValue;
     $item_desc=$x->item($i)->getElementsByTagName('description')
         ->item(0)->childNodes->item(0)->nodeValue;
     echo ("<p><a href='" . $item_link
         . "'>" . $item_title . "</a>");
     echo ("<br>");
     echo ($item_desc . "</p>");
 }
 ?>

When the request for the RSS feed is sent from JavaScript to the PHP file, what will happen is:

· Check which RSS feed is selected

· Create a new XML DOM object

· Load the RSS document in the xml variable

· From channel Extract and output the element

from the element Extract and output the element

from the item element The program execution result:

Continuing Learning

new file

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>PHP中文网(php.cn)</title> <script> function showRSS(str) { if (str.length==0) { document.getElementById("rssOutput").innerHTML=""; return; } if (window.XMLHttpRequest) { // IE7+, Firefox, Chrome, Opera, Safari 浏览器执行代码 xmlhttp=new XMLHttpRequest(); } else { // IE6, IE5 浏览器执行代码 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 && xmlhttp.status==200) { document.getElementById("rssOutput").innerHTML=xmlhttp.responseText; } } xmlhttp.open("GET","getrss.php?q="+str,true); xmlhttp.send(); } </script> </head> <body> <form> <select onchange="showRSS(this.value)"> <option value="">选择一个 RSS-feed:</option> <option value="rss">读取 RSS 数据</option> </select> </form> <br> <div id="rssOutput">RSS-feed 数据列表...</div> </body> </html>

submit Reset Code

Automatic operation

PHP AJAX RSS

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