In haloarene why its Ortho & para directing position shows electrophilic aromatic substitution?

Reason:

it is occur due to resonating structures of haloarene.look at the resonating sructures of phinyl chloride

(We concluded Ortho and para positions with respect to halogen atom)

from above resonating structures it is clear that its Ortho and para positions have maximum electron density.so its Ortho & para  positions attack electrophile(which have positive sign in it).

e.g

it is the answer to the question why haloaren shows electrophilic aromatic substitution reaction only at Ortho & para positions. Ok