function intervention_client(){
  $('step2_new').style.display="none";
  $('step2_client').style.display="block";
  $('step3').style.display="block";
}

function intervention_contact(){
  $('step2_client').style.display="none"; 
  $('step2_new').style.display="block";
  $('step3').style.display="block";
}