In the older days and still now we have buttons where one way is off and the other way is on, its mechanically built to connect or disconnect an electric path physically.
On modern devices like laptops the power buttons work differently. Push once its On, Push again it won't turn off and goto sleep mode instead. Keep the same button pressed for like 3 seconds exactly and the laptop shuts down as if the power was literally cut off. These buttons surely have a more complex mechanism than just connecting or disconnecting a wire. Does anyone know how their circuit has been designed? I am quite curious as to how these power switches work.