  We analyze the process $e p \to e p \phi$ near the threshold within $uud -
s\bar s$ cluster model as a probe of the strangeness content of proton. Our
consideration is based on the relativistic harmonic oscillator quark model
which takes into account the Lorentz-contraction effect of the hadron
wavefunctions. We find that the knockout mechanisms are comparable to the
diffractive production of vector-meson-dominance model when only (3-5)% strange
quark admixture is assumed, which should be compared with (10-20)% of the
nonrelativistic quark model prediction. The cross sections of the $uud$- and
$s\bar s$-knockout processes have qualitatively different dependence on the
four-momentum transfer squared to the proton and may be distinguished
experimentally. We also briefly discuss a way to determine the strangeness
content of proton in 5-quark cluster model.
