JSFiddle - React, Tailwind, and code Playground

HTML

<div id="inline1" data-test="Data"></div>
<div id="inline2" data-test="Data"></div>
<div id="output"></div>

JavaScript

var $output = $('#output');

function testInlineData1() {
    var elem = document.getElementById('inline1'),
        $elem = $(elem);

    $output.append('Inline1 Data / $.data: ' + $.data(elem, 'test') + '<br>');
    $output.append('Inline1 Data / $().data: ' + $elem.data('test') + '<br>');
    $output.append('Inline1 Data / $.data: ' + $.data(elem, 'test') + '<br>');
}
function testInlineData2() {
    var elem = document.getElementById('inline2'),
        $elem = $(elem);

    $output.append('Inline2 Data / $().data: ' + $elem.data('test') + '<br>');
    $output.append('Inline2 Data / $.data: ' + $.data(elem, 'test') + '<br>');
}


$(function() {
    testInlineData1();
    testInlineData2();
});