charge conservation

Maxwell's equations

∇・D = ρ

∇・B = 0

∇×E = - ∂B/∂ｔ

∇×H = i + ∂D/∂ｔ

taking divergence of the last equation,

∇・（∇×H ) = 0 = ∇・( i + ∂D/∂ｔ) = ∇・i + ∂(∇・D)/∂ｔ) = ∇・i + ∂ρ/∂ｔ

we get 

∇・i + ∂ρ/∂ｔ = 0 (charge conservation)

by way of trial, taking divergence of the third equation,

∇・(∇×E) = - ∂∇・B/∂ｔ

the left is zero using a formula of vector analysis,

the right also zero because ∇・B = 0, the second equation.

the results are trivial.