DOM-parsing/todo/internalSubset.html - external/github.com/web-platform-tests/wpt - Git at Google

 <!DOCTYPE html>
 ...
 <script>
 var p = new DOMParser(), s = new XMLSerializer();
 var doc = p.parseFromString("<!DOCTYPE foo [ <!ELEMENT foo (#PCDATA)> ]><foo/>", "text/xml")
 w(s.serializeToString(doc))
 </script>
 <table>
 <caption>Results</caption>
 <thead>
 <tr><th>UA<th>Result
 <tbody>
 <tr><th>Gecko<td><code>&lt;!DOCTYPE foo [ &lt;!ELEMENT foo (#PCDATA)> ]>\n&lt;foo/></code>
 <tr><th>WebKit<td><code>&lt;!DOCTYPE foo>&lt;foo/></code>
 <tr><th>Presto<td><code>&lt;?xml version="1.0"?>&lt;!DOCTYPE foo>&lt;foo/></code>
 </table>
	<!DOCTYPE html>
	...
	<script>
	var p = new DOMParser(), s = new XMLSerializer();
	var doc = p.parseFromString("<!DOCTYPE foo [ <!ELEMENT foo (#PCDATA)> ]><foo/>", "text/xml")
	w(s.serializeToString(doc))
	</script>
	<table>
	<caption>Results</caption>
	<thead>
	<tr><th>UA<th>Result
	<tbody>
	<tr><th>Gecko<td><code><!DOCTYPE foo [ <!ELEMENT foo (#PCDATA)> ]>\n<foo/></code>
	<tr><th>WebKit<td><code><!DOCTYPE foo><foo/></code>
	<tr><th>Presto<td><code><?xml version="1.0"?><!DOCTYPE foo><foo/></code>
	</table>