Re: Validator doesn't send HTTP_ACCEPT headers, "Conflict between Mime Type and Document Type" warning is incorrect.

On 31/07/07, Sierk Bornemann <> wrote:
> Of course, this would be sane. But how to translate into a working
> solution *without* asking the client's (in this case the valdator's)
> accept header?
> Any suggestion? Any algorithm out there (for PHP or JSP or other
> frameworks) does rely on the browser's accept header and asks for the
> *existance* of "application/xhtml+xml" in the accept header of the
> client.
> I, so far, have never seen any working solution, which asks for the
> *non-existance* of  "application/xhtml+xml". All implementations of
> the algorithm cited, I have seen so far, do ask for the *existance*
> of "application/xhtml+xml".
> So, how would you implement the *opposite* of that, if you have
> requesting user agents, which provide an empty accept header string
> or provide a meaningful "*" as the Internet Explorer does?

You could first check that there is an HTTP_ACCEPT header. If not,
deliver application/xhtml+xml; otherwise, test if
application/xhtml+xml is in the accept header. That caters for all the
scenarios you mentioned. The following serves text/html to IE,
application/xhtml+xml to Firefox (and other browsers that state they
can handle it), and application/xhtml+xml to the validator (as it
doesn't send the accept header):

header("Vary: Accept");
    if (stristr($_SERVER[HTTP_ACCEPT], "application/xhtml+xml") === FALSE) {
        header("Content-Type: text/html; charset=utf-8");
    else {
        header("Content-Type: application/xhtml+xml; charset=utf-8");
else {
    header("Content-Type: application/xhtml+xml; charset=utf-8");



Supplement your vitamins

Received on Tuesday, 31 July 2007 15:49:53 UTC