As you just said in comments, the laptop has a wide acceptable input range. That is not surprising since it is a switching power supply.
Others have discussed how laptop supplies (like a great many loads) simply do not care about frequency inside conceivable ranges. They state 50-60Hz because 50Hz or 60Hz is the frequency of essentially all terrestrial power.
As far as voltage, they are clearly stating a working range of 100-240V, and again they're just regurgitating the range of essentially all terrestrial power: 100V in Japan or 240V in the UK. The practical limits will be:
- too high a voltage causing insulation or component breakdown, but insulation is cheap.
- too low spikes are just a momentary low voltage, and the switcher will try to ride through it. The only risk is that it shouldn't spend minutes at too-low voltage, because lower voltage means the switcher will draw more current, and at a a point, that will overheat and burn up current pathways in the device.
I would advise getting a physical, copper-and-iron, wound stepdown transformer from 240V to 120V. That will passively dampen spikes, and smooth out some power issues. It will also divide the voltage by 2, meaning the power would have to jump to 480V before it would exceed the voltage spec.
A transformer built for 50Hz is slightly better. The size of the iron core decideds a transformer's ideal frequency, and 16% won't matter on a transformer this small. (I'm assuming 100-500 W).
Within sane range (say, maximum aircraft 400Hz)... Obviously, anything that rectifies doesn't care about frequency. Also, resistive heaters don't care about frequency. Things using a variable frequency drive don't care about input frequency, because they are slicing and dicing to make their own frequency.
Rotary machines (including transformers) do care, however. As alluded, transformers are tuned for a frequency by the size of their iron core; motors as well. A motor or transformer will be very, very unhappy on railroad 16.7 Hz or aircraft 400Hz.
Clocks depend on 50/60Hz being right on the button. There was a newspaper-worthy scandal in the EU as the grid operators were not able to sustain 50.000 Hz, and had to "speed up the grid" in the evening to catch everyone's clock up by the few seconds they had drifted. The grid is managed that precisely.