PHP Example - AJAX RSS Reader

An RSS Reader is used to read RSS Feeds.


The following example will demonstrate an RSS reader, where the RSS-feed is loaded into a webpage without reloading:

RSS-feed will be listed here...

Example Explained - The HTML Page

When a user selects an RSS-feed in the dropdown list above, a function called "showRSS()" is executed. The function is triggered by the "onchange" event:

function showRSS(str) {
  if (str.length==0) {
  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) {

<select onchange="showRSS(this.value)">
<option value="">Select an RSS-feed:</option>
<option value="Google">Google News</option>
<option value="NBC">NBC News</option>
<div id="rssOutput">RSS-feed will be listed here...</div>

The showRSS() function does the following:

  • Check if an RSS-feed is selected
  • Create an XMLHttpRequest object
  • Create the function to be executed when the server response is ready
  • Send the request off to a file on the server
  • Notice that a parameter (q) is added to the URL (with the content of the dropdown list)

The PHP File

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

//get the q parameter from URL

//find out which feed was selected
if($q=="Google") {
} elseif($q=="NBC") {

$xmlDoc = new DOMDocument();

//get elements from "<channel>"
$channel_title = $channel->getElementsByTagName('title')
$channel_link = $channel->getElementsByTagName('link')
$channel_desc = $channel->getElementsByTagName('description')

//output elements from "<channel>"
echo("<p><a href='" . $channel_link
  . "'>" . $channel_title . "</a>");
echo($channel_desc . "</p>");

//get and output "<item>" elements
for ($i=0; $i<=2; $i++) {
  echo ("<p><a href='" . $item_link
  . "'>" . $item_title . "</a>");
  echo ("<br>");
  echo ($item_desc . "</p>");

When a request for an RSS feed is sent from the JavaScript, the following happens:

  • Check which feed was selected
  • Create a new XML DOM object
  • Load the RSS document in the xml variable
  • Extract and output elements from the channel element
  • Extract and output elements from the item elements