PHP Example – AJAX and XML

AJAX can be used for interactive communication with an XML file.

AJAX XML Example

The following example will demonstrate how a web page can fetch information from an XML file with AJAX:

Example Explained – The HTML Page

When a user selects a CD in the dropdown list above, a function called “showCD()” is executed. The function is triggered by the “onchange” event:

The showCD() function does the following:

• Check if a CD 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 “getcd.php”.

The PHP script loads an XML document, “cd_catalog.xml“, runs a query against the XML file, and returns the result as HTML:

When the CD query is sent from the JavaScript to the PHP page, the following happens:

1. PHP creates an XML DOM object
2. Find all <artist> elements that matches the name sent from the JavaScript
3. Output the album information (send to the “txtHint” placeholder)