JSFiddle - React, Tailwind, and code Playground

HTML

<h2>Sélectionner une date de concert</h2>
<input type="checkbox"  id="1" name="date[]" value="Samedi 14 Décembre 2013, 20h" />Samedi 14 Décembre 2013, 20h - Temple de Morges<br /><br />
<div class="hidden 1">
   <div id="phone_number_form" class="hidden">
      <p>
         <select name="sele-personne">
            <option>
               Cat 1 - Adulte				
            </option>
            <option>
               Cat 2 - Adulte				
            </option>
            <option>
               Cat 3 - Adulte				
            </option>
            <option>
               Cat 1 - Etudiant				
            </option>
            <option>
               Cat 2 - Etudiant				
            </option>
            <option>
               Cat 3 - Etudiant				
            </option>
            <option>
               Cat 1 - Enfant				
            </option>
            <option>
               Cat 2 - Enfant				
            </option>
            <option>
               Cat 3 - Enfant				
            </option>
         </select>
         <input type="number" style="width:35px;" id="quantitee" value="1" min="1" max="50"/>
         <input type="texte" readonly value="" />
         <input type="button" id="remove_phone_number" value="Supprimer">
      </p>
   </div>
   <form>
      <p>
         <input type="button" value="Ajouter une personne" id="add_phone_number">
      </p>
   </form>
</div>
<input type="checkbox"  id="2" name="date[]" value="Samedi 15 Décembre 2013, 20h" />Samedi 15 Décembre 2013, 20h - Temple de Morges<br /><br />
<div class="hidden 2">
   <div id="phone_number_form" class="hidden">
      <p>
         <select name="sele-personne">
            <option>
               Cat 1 - Adulte				
            </option>
            <option>
               Cat 2 - Adulte				
            </option>
            <option>
               Cat 3 - Adulte				
            </option>
            <option>
               Cat 1 - Etudiant				
            </option>
            <option>
          ...

CSS

.hidden {
    display: none;
}

JavaScript

$(document).ready(function(){
		
    var phone_number_form_index=0;
    $("#add_phone_number").click(function(){
        phone_number_form_index++;
        $(this).parent().before($("#phone_number_form").clone().attr("id","phone_number_form" + phone_number_form_index));
        $("#phone_number_form" + phone_number_form_index).css("display","inline");
        $("#phone_number_form" + phone_number_form_index + " :input").each(function(){
            $(this).attr("name",$(this).attr("name") + phone_number_form_index);
            $(this).attr("id",$(this).attr("id") + phone_number_form_index);
            });
        $("#remove_phone_number" + phone_number_form_index).click(function(){
            $(this).closest("div").remove();
        });
    }); 
	
	$('.hidden').hide();

$(':checkbox').change(function() {
    changeCheck(this);
});

$(':checkbox:checked').each(function(){
    changeCheck(this);
});

function changeCheck(x) {
    var option = $(x).attr('id');
    if ($('.' + option).is(':visible')) {
        $('.' + option).fadeOut();
    }
    else {
        $('.' + option).fadeIn();
    }
}

});