8. An apparatus according to claim 1 , wherein condition (a) is satisfied.
8. An apparatus according to claim 1 , wherein condition (a) is satisfied. 14. An apparatus according to claim 8 , wherein in the case that the Javascript in the HTTP response uses the first random number function to generate a URL, then the modified Javascript uses the algorithm different from the first random number algorithm instead of the first random number function to generate a URL, and execution of the modified Javascript by two apparatuses including the client device results in generation of the same URL by each of the two apparatuses.