Magnetism and Gauss' law:
The net magnetic flux (∅B) through any closed surface is always zero.
This law states that the number of magnetic field lines living any closed surface is always equal to the number of magnetic field lines entering it.
Let a closed surface S is held in a uniform magnetic field B. Now we consider a small vector area element ∆s of this surface.
The difference between the gauss' law of Magnetism and electrostatic is that isolated magnetic poles(mono poles) are not known to exist.