PHP check to make sure request is either xmlhttp from my site or normal request from a certain domain

Question

How would the condition be written to ensure a page is either accessed by xmlhttp request from my site or from an allowed outside domain?

Answer 1

You spelt referrer correctly but unfortunately the person who wrote the HTTP spec couldn't! You need to use HTTP_REFERER.

You might also want to escape the dot \. so it only matches a dot and not everything.