PHP Example - AJAX RSS Reader

An RSS Reader is used to read RSS Feeds.

Example Explained - The HTML Page

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

Select an RSS-feed: Google News MSNBC News RSS-feed will be listed here...

The showResult() 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)

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The PHP File

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

load($xml); //get elements from "" $channel=$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; //output elements from "" echo(" " . $channel_title . ""); echo(" "); echo($channel_desc . " "); //get and output "" elements $x=$xmlDoc->getElementsByTagName('item'); for ($i=0; $i<=2; $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 (" " . $item_title . ""); echo (" "); echo ($item_desc . " "); } ?>

When 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 element