  The formalism to describe electron scattering reactions on two-neutron halo
nuclei is developed. The halo nucleus is described as a three-body system
(core+n+n), and the wave function is obtained by solving the Faddeev equations
in coordinate space. We discuss elastic and quasielastic scattering using the
impulse approximation to describe the reaction mechanism. We apply the method
to investigate the case of electron scattering on $^6$He. Spectral functions,
response functions, and differential cross sections are calculated for both
neutron knockout and $\alpha$ knockout by the electron.
