dataset js

for javascript : 
webappData.getAttribute('data-id');
document.querySelector('#elementId').dataset.id = 'value';

for jquery : 
$(element).attr('data-key', 'value');//html file
<div id="user" data-user-id="2" data-user-date-of-birth="03/03/1993">
 <p> Hello ! </p>
</div>

//js file
const user = document.getElementById('user')

console.log(user.dataset.userId) // => 2

console.log(user.dataset.userDateOfBirth) // => '03/03/1993'