Ottenere il nome del browser

<?php
function jacoz_browser_in_use()
{
	$user_agent = $_SERVER['HTTP_USER_AGENT'];
	if (eregi("MSIE", $user_agent) && !eregi("Opera", $user_agent)) {
		$return = "Internet Explorer";
	} elseif (eregi("Firefox", $user_agent)) {
		$return = "Mozilla Firefox";
	} elseif (eregi("Opera", $user_agent)) {
		$return = "Opera";
	} elseif (eregi("Gecko", $user_agent)) {
		$return = "Netscape Navigator";
	} else {
		$return = "Browser sconosciuto";
	}

	return $return;
}

echo jacoz_browser_in_use();
?>