"safest" way to use the AC authority supply for your laptop?

When your laptop is already ON and you want to use ELEMENT power supply a bit than artillery dominion.....should you

A) Bung power supply into divider outlet FIRST and PAST lid it into your laptop?
or
B) Plug your cord into the laptop FIRST and PAST block it into the wall outlet?

Is there a difference? Does either way have AN affect on your laptop's battery--as far a sudden surge of power is concerned?