  We investigate the electromagnetic form factors of nucleons within a simple
relativistic quark spectator-diquark model using the light-cone formalism.
Melosh rotations are applied to both quark and vector diquark. It is shown that
the difference between vector and scalar spectator diquarks reproduces the
right electric form factor of neutrons, and both the form factors $G_E(Q^2)$
and $G_M(Q^2)$ of the proton and neutron agree with experimental data well up
to $Q^2=2 ~\rm{GeV}^2$ in this simple model.
