@NogDogAug 13.2006 — #From the [url=http://us3.php.net/manual/en/reserved.variables.php#reserved.variables.server]description[/url], it would appear $_SERVER['SERVER_PROTOCOL'] will tell you that.
@bokehAug 13.2006 — #Since at least 95% of websites are hosted under named based virtual hosts (i.e. they share an IP with other sites), which requires browsers to be HTTP/1.1 compliant, it is very unlikely anyone is using non-HTTP/1.1 compliant browsers any more and if they were then they wouldn't be able to view very many websites.