$request = sfContext::getInstance()->getRequest(); if ($request->isXmlHttpRequest()) { // Output JSON or another format for AJAX requests } else { // Output HTML for non-AJAX requests }Another example of using isXmlHttpRequest() method is for logging user activities. You can use it to distinguish between user-initiated requests and background requests, such as periodic updates to a webpage. The package library that the sfWebRequest class belongs to, is Symfony HttpFoundation component. This component provides a set of PHP classes and functions that provide a more object-oriented approach to handling HTTP requests and responses.