input field date format change code example

Example: input type date on change

var date_input = document.getElementById('date_input');
date_input.valueAsDate = new Date();

date_input.onchange = function(){
   console.log(this.value);
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="date" id='date_input'>