JSFiddle - React, Tailwind, and code Playground

HTML

<span data-value="test"></span>
<div></div>

JavaScript

function mylog(text) {
    $("div").append(text+"<br>");
}

mylog($("span").data("value"));
mylog($("span").attr("data-value"));
mylog("-------");
$("span").data("value", "datachanged");
mylog($("span").data("value"));
mylog($("span").attr("data-value"));
mylog("-------");
$("span").attr("data-value", "attrchanged");
mylog($("span").data("value"));
mylog($("span").attr("data-value"));
mylog("-------");