doctype returns null

[SmartLayer]

The same XML document behave differently in browser and with xmldom.

First, in browser (Firefox 75)

<script>
xml = '<?xml version="1.0" encoding="UTF-8"?>'
xml = xml + "\n<!DOCTYPE tag1 [\n"
xml = xml + "<!ENTITY hello \"hello1\">\n"
xml = xml + "<!ENTITY there \"there1\">\n"
xml = xml + "]>\n"
xml = xml + "<tag1>Stuff in &hello;</tag1>"

  var parser = new DOMParser();
  var xmlDoc = parser.parseFromString(xml, "text/xml");
  alert(xmlDoc.doctype);
</script>

Result: [object DocumentType]

Then, the same XML document with xmldom

xml = '<?xml version="1.0" encoding="UTF-8"?>'
xml = xml + "\n<!DOCTYPE tag1 [\n"
xml = xml + "<!ENTITY hello \"hello1\">\n"
xml = xml + "<!ENTITY there \"there1\">\n"
xml = xml + "]>\n"
xml = xml + "<tag1>Stuff in here</tag1>"
var DOMParser = require('xmldom').DOMParser;
var doc = new DOMParser().parseFromString(xml);
console.info(doc.doctype);

Result: null (the attribute doctype does exist, its value is null)

The document used in these examples:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE tag1 [
<!ENTITY hello "hello1">
<!ENTITY there "there1">
]>
<tag1>Stuff in here</tag1>