It is valid (albeit silly) to specify lang;q=1.000 No more than three decimals are...

(rfc2616 section 3.9: Quality Values)
The language-range may contain more than one - (section 14.4) such as x-pig-latin
(section 3.10: Language Tags)

diff --git a/includes/WebRequest.php b/includes/WebRequest.php
index 2721a5b..daab86f 100644 (file)
--- a/includes/WebRequest.php
+++ b/includes/WebRequest.php
@@ -962,7 +962,7 @@ HTML;
 
                // Break up string into pieces (languages and q factors)
                $lang_parse = null;
-               preg_match_all( '/([a-z]{1,8}(-[a-z]{1,8})?|\*)\s*(;\s*q\s*=\s*(1|0(\.[0-9]+)?)?)?/',
+               preg_match_all( '/([a-z]{1,8}(-[a-z]{1,8})*|\*)\s*(;\s*q\s*=\s*(1(\.0{0,3})?|0(\.[0-9]{0,3})?)?)?/',
                        $acceptLang, $lang_parse );
 
                if ( !count( $lang_parse[1] ) ) {