如何在Firefox扩展中将HTML字符串转换为DOM对象？

function htmlStringToDOMDocument(htmlString) {
  const parser = new DOMParser();
  const doc = parser.parseFromString(htmlString, 'text/html');
  return doc;
}

const htmlString = '<div><p>Hello, world!</p></div>';
const doc = htmlStringToDOMDocument(htmlString);
const domObject = doc.body.firstChild;

function htmlStringToDOMObject(htmlString) {
  const tempElement = document.createElement('div');
  tempElement.innerHTML = htmlString;
  return tempElement.firstChild;
}

const htmlString = '<div><p>Hello, world!</p></div>';
const domObject = htmlStringToDOMObject(htmlString);