JSFiddle - React, Tailwind, and code Playground
HTML
<section>
<h2>Test</h2>
<pre id="result"></pre>
</section>JavaScript
var xml = '<?xml version="1.0"?><root/>';
var regex = /^.+<\?xml/i;
var test = regex.test(xml);
var result = 'Checking ' + regex + ".test('" + xml + "'): " + test;
console.log(result);
document.getElementById('result').textContent = result;