JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://www.kafu-shop.de/js/testdata.js"></script>
<h1>Testresults</h1>
<h2>Original Regular Exression</h2>
<div id="test_result_org"></div>
<h2>Modified Regular Exression</h2>
<div id="test_result_modified"></div>

JavaScript

var attrRegExp_org = /([\w:\-]+)(?:\s*=\s*(?:(?:\"((?:[^\"])*)\")|(?:\'((?:[^\'])*)\')|([^>\s]+)))?/g;
var attrRegExp_modified = /([\w:\-]+)(?:\s*=\s*(?:(?:\"([^\"]*)\")|(?:\'([^\']*)\')|([^>\s]+)))?/g

var matches_org = testdata.match(attrRegExp_org);
var matches_modified = testdata.match(attrRegExp_modified);

if (matches_org) {
    $(document.getElementById("test_result_org")).text("ok:" + matches_org.join(" "));
}
if (matches_modified) {
    $(document.getElementById("test_result_modified")).text("ok:" + matches_modified.join(" "));
}