f[x_,y_,z_] := Div[{2x*y^3z^4, 3x^2y^2z^4, 4x^2y^3z^3}, {x, y, z}]
f[x,y,z]

g[x_,y_,z_]=If[Sqrt[x^2+y^2+z^2]<2,Div[{2x*y^3z^4, 3x^2y^2z^4, 4x^2y^3z^3}, {x, y, z}],0]
g[1,1,1]