OT: laptop power auto-continuation?

Laptops, of course, run on house current or internal batteries. Our desktop,
also of course, runs on house current alone, but gets that current through a
combo surge protector/battery back-up UPS [ours by APC]. When the power goes
out, which is not uncommon where we live, the UPS automatically gives us
enough time to shut the desktop down so no data's lost.

So, the question. We're looking at a laptop [we're never owned one] for a
soon-to-be college student, but don't know if --while running on house
current, and hooked to its own surge protector-- the laptop's batteries
would automatically takeover during a house current outage. Does the answer
depend on the laptop brand, or do they all switch over, or what? There's no
point getting a UPS for the laptop if only a surge protector is needed.

Obviously we can ask at the stores [they're closed now] but the thought just
occurred to me so RAAM seemed the place to ask first.