PHP super properties for utm params

utm_params.php

// assuming you have already imported the Mixpanel PHP library
$mp = Mixpanel::getInstance("MIXPANEL_PROJECT_TOKEN");

// register every utm parameter as a super property
foreach($_GET as $param => $param_val) {
	if (strstr($param, 'utm_') === 0) {
		$mp->register($param, $param_val);
	}
}

// track an event which will have the utm params as properties
$mp->track("button clicked");