Question on Slaying and Bane mods

So about these mods like charrslaying or deathbane, do these mods give bonus damage done by spells or is it just the weapon.

As with other damage mods, they only apply to damage done through attacks with the modified weapon, and spells are not considered attacks. This is also why spellcaster weapons (staves, wands) should never be modded with 15^50 or similar stuff.

Attacks and ofcourse attack skills.