  We compute numerically the sequence of successive pinned configurations of an
elastic line pulled quasi-statically by a spring in a random bond (RB) and
random field (RF) potential. Measuring the fluctuations of the center of mass
of the line allows to obtain the functional renormalization group (FRG)
functions at the depinning transition. The universal form of the second
cumulant Delta(u) is found to have a linear cusp at the origin, to be identical
for RB and RF, different from the statics, and in good agreement with 2-loop
FRG. The cusp is due to avalanches, which we visualize. Avalanches also produce
a cusp in the third cumulant, whose universal form is obtained, as predicted by
FRG.
