  For the first time, a phenomenological analysis of the experimental
electromagnetic form factors of the nucleon, both in the timelike and spacelike
regions, is performed by taking into account the effects of nonvalence
components in the nucleon state, within a light-front framework. Our model,
based on suitable Ansatzes for the nucleon Bethe-Salpeter amplitude and a
microscopic version of the well-known Vector Meson Dominance model, has only
four free parameters (determined by the spacelike data with $\chi^2/datum \sim
1.7$), and yields a nice description of the experimental electromagnetic form
factors in the physical region in the range $-30 (GeV/c)^2 < q^2 < 20
(GeV/c)^2$, except for the neutron one in the timelike region. Valuable
information can be gained in the timelike region on possible missing Vector
Mesons around $q^2 \sim 4.5 (GeV/c)^2$ and $q^2 \sim 8.0 (GeV/c)^2$
