Danish–Norwegian mutual intelligibility

I just skimmed over an email exchange between someone writing in Danish and someone writing in Norwegian, and it made me wonder how mutually intelligible those languages are in their written form (using specifically Bokmål for Norwegian).

I mean, I know they're fairly close, but I wonder *how* close, in terms I can "bellyfeel".

I imagine, further apart than UK English and US English, but closer than German and Dutch... perhaps like Standard German and written Züritüütsch or something? Or closer than that?