diff --git a/dom.bs b/dom.bs
index 7751190a..907c7386 100644
--- a/dom.bs
+++ b/dom.bs
@@ -4689,8 +4689,12 @@ invoked, must run these steps:
  <li>If <var>is</var> is non-null and <var>definition</var> is null, then <a>throw</a> a
  {{NotFoundError}}.
 
+ <li>Let <var>namespace</var> be the <a>HTML namespace</a> if the <a>context
+ object</a>'s <a for=Document>content type</a> is "<code>text/html</code>" or
+ "<code>application/xhtml+xml</code>", and null otherwise.
+
  <li>Let <var>element</var> be the result of <a>creating an element</a> given the
- <a>context object</a>, <var>localName</var>, null, the <a>HTML namespace</a>, <var>is</var>, and
+ <a>context object</a>, <var>localName</var>, null, <var>namespace</var>, <var>is</var>, and
  with the <var>synchronous custom elements</var> flag set. Rethrow any exceptions.
 
  <li>If <var>is</var> is non-null, then <a>set an attribute value</a> for <var>element</var> using