Depend on getting page response (5)
I believe the answer is:
reply
'response' is the definition.
('reply' can be a synonym of 'response')
'depend on getting page' is the wordplay.
'depend' becomes 'rely' (I've seen this before).
'on' means one lot of letters goes inside another (as in clothing \'on\' a person).
'getting page' becomes 'p' (I can't explain this - if you can you should give a lot more credence to this answer).
'rely' enclosing 'p' is 'REPLY'.
(Other definitions for reply that I've seen before include "Counter" , "counterattack?" , "Come back" , "Returned statement" , "Retort" .)