javascript how to select custom attribute code example

Example 1: javascript get data-id attribute

//get data-id attribute in plain Javascript
var element = document.getElementById('myDivID');
var dataID = element.getAttribute('data-id');

//get data-id using jQuery
var dataID = $('myDivID').data('data-id');

Example 2: dataset js

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

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