  Light-front dynamics(LFD) plays an important role in hadron phenomenology as
evidenced from recent development of generalized parton distributions and other
quantities involving hadrons. For successful LFD applications to hadron
phenomenology, however, treacherous points such as zero-mode contributions
should be taken into account. For a concrete example of zero-mode contribution,
we present Standard Model analysis of vector anomaly in the CP-even form
factors of W^{\pm} gauge bosons. Main distinguished features of LFD is
discussed in comparison with other Hamiltonian dynamics. We also present a
power counting method to correctly pin down which hadron form factors receive
the zero-mode contribution and which ones do not. Indications from our analysis
to hadron phenomenology are discussed.
