xml/xml-bom.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>XML parsing with Byte Order Mark (BOM)</title>
<link rel="help" href="https://www.w3.org/TR/REC-xml/#sec-guessing">
<link rel="help" href="https://html.spec.whatwg.org/multipage/dynamic-markup-insertion.html#the-domparser-interface">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
'use strict';

const testCases = [
  {
    title: 'application/xml with BOM before XML declaration',
    xml: '\uFEFF<?xml version="1.0"?><foo/>',
    type: 'application/xml',
    expectedRoot: 'foo',
  },
  {
    title: 'application/xml with BOM without XML declaration',
    xml: '\uFEFF<foo/>',
    type: 'application/xml',
    expectedRoot: 'foo',
  },
  {
    title: 'text/xml with BOM before XML declaration',
    xml: '\uFEFF<?xml version="1.0"?><foo/>',
    type: 'text/xml',
    expectedRoot: 'foo',
  },
  {
    title: 'text/xml with BOM without XML declaration',
    xml: '\uFEFF<foo/>',
    type: 'text/xml',
    expectedRoot: 'foo',
  },
  {
    title: 'image/svg+xml with BOM',
    xml: '\uFEFF<svg xmlns="http://www.w3.org/2000/svg"/>',
    type: 'image/svg+xml',
    expectedRoot: 'svg',
  },
];

for (const { title, xml, type, expectedRoot } of testCases) {
  test(() => {
    const doc = new DOMParser().parseFromString(xml, type);
    const parsererror = doc.querySelector('parsererror');
    assert_equals(parsererror, null, 'Should not contain parsererror: ' + (parsererror ? parsererror.textContent : ''));
    assert_equals(doc.documentElement.localName, expectedRoot);
    assert_equals(doc.contentType, type);
  }, `DOMParser parses ${title}`);
}
</script>