NCBI/PubChemNCI/CIR
(1) PUG http sync (failing in FF) (2) PUG https sync (works)
PUG http async (failing in FF) PUG https async (works)

FETCH http async (failing in FF) FETCH https async (works)
FETCH http async (failing in FF) FETCH https async (works)

Click link (1), then (2), then (1) again, each time looking for a response.
Apparently, after HSTS has been initiated by (2), (1) will not work again.
The browser is not properly auto-switching to HTTPS from HTTP in AJAX.
This is specifically an AJAX problem. 		test http sync (works) test https sync (will time out)
test http async (works) test https async (will time out)

NCI's Chemical Identifier Resolver does not provide https service.
This is a different problem.