The dataset read-only property of the HTMLElement interface provides read/write access to custom data attributes (data-*) on elements. It exposes a map of strings (DOMStringMap) with an entry for each data- attribute.
HTMLElement.dataset
<div id="demo" data-user="john"></div>
<script>
const element = document.getElementById('demo');
// Set a data attribute.
element.dataset.dateOfBirth = '2000-10-10';
// HTML: <div id="demo" data-user="john" data-date-of-birth="2000-10-10"></div>
delete element.dataset.dateOfBirth;
// HTML: <div id="demo" data-user="john"></div>
</script>