Test case for Greasemonkey issue #1571

dataset-test.user.js

// ==UserScript==
// @name    dataset test
// @version 1
// @include *
// ==/UserScript==

var el_work = document.createElement('div');
el_work.id = 'el_work';
el_work.setAttribute('data-test2', 'test');
document.head.appendChild(el_work);

var el_fail = document.createElement('div');
el_fail.id = 'el_fail';
el_fail.dataset.test1 = 'test';
document.head.appendChild(el_fail);

setTimeout(function() {
  dump('el_work: ' + document.getElementById('el_work').dataset.test2 + '\n');
  dump('el_fail: ' + document.getElementById('el_fail').dataset.test1 + '\n');
  dump(document.head.innerHTML + '\n');
}, 500);