For HTTP responses with Content-Types suggesting character data, which charset should be assumed by the client if none is specified?

Question

If no charset parameter is specified in the Content-Type header, RFC2616 section 3.7.1 seems to imply ISO8859-1 should be assumed for media types of subtype "text":

Answer 1

Pointing out the obvious: "application/x-javascript" is not a subtype of "text".

Also, the text in RFC 2616 is outdated. The next revision of HTTP/1.1 will not define a default. See RFC 6657 for further information.