Andy, I continue this thread to discuss your comments in the wiki. Cut-n-paste from wiki: "HTTP header field values which contain separator characters MUST be properly quoted according to RFC 2616. Is this necessary? It could be assumed that the value of the header is the text immediately following the '=' character. Would be useful to have a list of these separator characters" Yes, it is necessary. If you have an attribute containing a comma (",") you would break the comma-separated list representation of HTTP header field values. According to RFC2616 the following two examples are be equivalent. Attribute: foo="bar,foo" Attribute: key=value Attribute: foo="bar,foo", key=value The list of separators are specified in RFC2616. regards, Ralf