Hello.
I block again on construct 2 at the POST request level.
Ajax communicates well with my file because they return the echo to me.
except that I have the impression that AJAX does not return the pseudo field to php.
header("Access-Control-Allow-Origin: *");
if(!empty($_POST["register_pseudo"])){
echo "entrer";
}else{
echo "le champ pseudo ne peut pas etre vide";
}