get this data attribute code example

Example 1: dataset js

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

for jquery : 
$(element).attr('data-key', 'value');

Example 2: data attribute html

<!-- data-* attritubes can be used on any html element -->
<div data-my-custom-data="true"></div>