I'm making the request in the following way:
var myScript = eltCreate('script'); myScript.setAttribute('src','http://myserver.com/script'); document.body.appendChild(myScript);
In a fit of confused desperation, I changed the script page to simply output "My cookie has [x] elements" where [x] is
count($_COOKIE). If this extremely small subset of users requests the script via the normal method, the message reads "My cookie has 0 elements". When they access the URL directly in their browser, the message reads "My cookie has 7 elements".
What on earth could be going on?!