PHP Example - AJAX RSS Reader
RSS Reader is used to read RSS Feed.
AJAX RSS Reader
In the following example, we will demonstrate an RSS reader through which the content from RSS is not refreshed on the web page. The following is loaded:
Example explanation-HTML page
When the user selects an RSS in the drop-down list above- feed, a function named "showRSS()" will be executed. This function is triggered by the "onchange" event:
<html>
<head>
<meta charset="utf-8">
<title>php中文网</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:
##· off · The function created at the server response when it is ready · Send a request to the file on the server . Contents of the drop-down list)PHP fileFile rss_demo.xml. The server page called through JavaScript in the above paragraph is a PHP file named "getrss.php":<?php
// 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: · off out off out off out out out out out out out through out through use use through through through through through through through through through through through through through throughthroughthroughthroughdownthroughdownunderdowndown‐‐‐‐ whip‐‐‐‐‐‐‐whip whiwhi whi whi behalf . Extract and output the element from the element Extract and output the element from the item elementNext Section