The select value is not passed by the post method. How to fix?

There is a code:

<form method="POST" id="select"> <select name="day"> <option disabled>День</option> {{#each day}} <option>{{this}}</option> {{/each}} </select> <select name="month"> <option disabled>Месяц</option> {{#each month}} <option value="{{this}}">{{this}}</option> {{/each}} </select> <select name="year"> <option disabled>Год</option> {{#each year}} <option value="{{this}}">{{this}}</option> {{/each}} </select> 

check in

When you try to transfer these values ​​to the server, an error occurs:

 TypeError: Cannot read property '3' of undefined 

Help me please. What is the mistake?