JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="coco">
    <li data-name="moi">test </li>
    <li data-name="lui">test 2 </li>
    <li data-name="toto">test </li>
</ul>

JavaScript

var liste, listeLi,i,monElement;

liste =  document.getElementById('coco');
listeLi = liste.getElementsByTagName('li');

for(i = 0; i < listeLi.length;  i++ ){
    monElement = listeLi[i];
    alert(monElement.dataset.name);
}