PHP Example - AJAX RSS Reader
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An RSS Reader is used to read RSS Feeds.
AJAX RSS Reader
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:
<html>
<head>
<script>
function showRSS(str) {
if (str.length==0) {
document.getElementById("
return;
}
if (window.XMLHttpRequest) {
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
} else { // code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.
}
xmlhttp.onreadystatechange=
if (this.readyState==4 && this.status==200) {
document.getElementById("
}
}
xmlhttp.open("GET","getrss.
xmlhttp.send();
}
</script>
</head>
<body>
<form>
<select onchange="showRSS(this.value)"
<option value="">Select an RSS-feed:</option>
<option value="Google">Google News</option>
<option value="NBC">NBC News</option>
</select>
</form>
<br>
<div id="rssOutput">RSS-feed will be listed here...</div>
</body>
</html>
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":
<?php
//get the q parameter from URL
$q=$_GET["q"];
//find out which feed was selected
if($q=="Google") {
$xml=("http://news.google.com/
} elseif($q=="NBC") {
$xml=("http://rss.msnbc.msn.
}
$xmlDoc = new DOMDocument();
$xmlDoc->load($xml);
//get elements from "<channel>"
$channel=$xmlDoc->
$channel_title = $channel->
->item(0)->childNodes->item(0)
$channel_link = $channel->
->item(0)->childNodes->item(0)
$channel_desc = $channel->
->item(0)->childNodes->item(0)
//output elements from "<channel>"
echo("<p><a href='" . $channel_link
. "'>" . $channel_title . "</a>");
echo("<br>");
echo($channel_desc . "</p>");
//get and output "<item>" elements
$x=$xmlDoc->
for ($i=0; $i<=2; $i++) {
$item_title=$x->item($i)->
->item(0)->childNodes->item(0)
$item_link=$x->item($i)->
->item(0)->childNodes->item(0)
$item_desc=$x->item($i)->
->item(0)->childNodes->item(0)
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
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An RSS Reader is used to read RSS Feeds.
AJAX RSS Reader
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:
<html>
<head>
<script>
function showRSS(str) {
if (str.length==0) {
document.getElementById("
return;
}
if (window.XMLHttpRequest) {
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
} else { // code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.
}
xmlhttp.onreadystatechange=
if (this.readyState==4 && this.status==200) {
document.getElementById("
}
}
xmlhttp.open("GET","getrss.
xmlhttp.send();
}
</script>
</head>
<body>
<form>
<select onchange="showRSS(this.value)"
<option value="">Select an RSS-feed:</option>
<option value="Google">Google News</option>
<option value="NBC">NBC News</option>
</select>
</form>
<br>
<div id="rssOutput">RSS-feed will be listed here...</div>
</body>
</html>
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":
<?php
//get the q parameter from URL
$q=$_GET["q"];
//find out which feed was selected
if($q=="Google") {
$xml=("http://news.google.com/
} elseif($q=="NBC") {
$xml=("http://rss.msnbc.msn.
}
$xmlDoc = new DOMDocument();
$xmlDoc->load($xml);
//get elements from "<channel>"
$channel=$xmlDoc->
$channel_title = $channel->
->item(0)->childNodes->item(0)
$channel_link = $channel->
->item(0)->childNodes->item(0)
$channel_desc = $channel->
->item(0)->childNodes->item(0)
//output elements from "<channel>"
echo("<p><a href='" . $channel_link
. "'>" . $channel_title . "</a>");
echo("<br>");
echo($channel_desc . "</p>");
//get and output "<item>" elements
$x=$xmlDoc->
for ($i=0; $i<=2; $i++) {
$item_title=$x->item($i)->
->item(0)->childNodes->item(0)
$item_link=$x->item($i)->
->item(0)->childNodes->item(0)
$item_desc=$x->item($i)->
->item(0)->childNodes->item(0)
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
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