diff --git a/mozilla/content/xml/document/src/nsXMLContentSink.cpp b/mozilla/content/xml/document/src/nsXMLContentSink.cpp
index 70a1da0d56d..1d7027d9d4c 100644
--- a/mozilla/content/xml/document/src/nsXMLContentSink.cpp
+++ b/mozilla/content/xml/document/src/nsXMLContentSink.cpp
@@ -42,6 +42,7 @@
 #include "nsICSSParser.h"
 #include "nsICSSStyleSheet.h"
 #include "nsHTMLAtoms.h"
+#include "nsLayoutAtoms.h"
 #include "nsIScriptContext.h"
 #include "nsIScriptContextOwner.h"
 #include "nsINameSpace.h"
@@ -430,7 +431,13 @@ nsXMLContentSink::AddAttributes(const nsIParserNode& aNode,
     nsIAtom* nameSpacePrefix = CutNameSpacePrefix(name);
     nsIAtom* nameAtom = NS_NewAtom(name);
     PRInt32 nameSpaceID = GetNameSpaceId(nameSpacePrefix);
-    if ((kNameSpaceID_None == nameSpaceID) && aIsHTML) {
+    if ((kNameSpaceID_XMLNS == nameSpaceID) && aIsHTML) {
+      NS_RELEASE(nameAtom);
+      name.Insert("xmlns:", 0);
+      nameAtom = NS_NewAtom(name);
+      nameSpaceID = kNameSpaceID_HTML;
+    }
+    else if ((kNameSpaceID_None == nameSpaceID) && aIsHTML) {
       nameSpaceID = kNameSpaceID_HTML;
     }
 
diff --git a/mozilla/content/xml/tests/docbooktest.xml b/mozilla/content/xml/tests/docbooktest.xml
index c51d434ff78..75a9fa8d089 100644
--- a/mozilla/content/xml/tests/docbooktest.xml
+++ b/mozilla/content/xml/tests/docbooktest.xml
@@ -6,6 +6,9 @@ Inc.</Title>
 <p xmlns="http://www.w3.org/TR/REC-html40" xmlns:h="http://www.w3.org/TR/REC-html40">
 <h:img src="flamer.gif"/>
 <img src="flamer.gif"/>
+<button>
+<h1>Some text</h1>
+</button>
 </p>
 <BookInfo> <BookBiblio> <Title>Demo Product Documentation</Title>
 <AuthorGroup><CorpAuthor>SoftQuad Inc.</CorpAuthor></AuthorGroup> 
diff --git a/mozilla/layout/xml/document/src/nsXMLContentSink.cpp b/mozilla/layout/xml/document/src/nsXMLContentSink.cpp
index 70a1da0d56d..1d7027d9d4c 100644
--- a/mozilla/layout/xml/document/src/nsXMLContentSink.cpp
+++ b/mozilla/layout/xml/document/src/nsXMLContentSink.cpp
@@ -42,6 +42,7 @@
 #include "nsICSSParser.h"
 #include "nsICSSStyleSheet.h"
 #include "nsHTMLAtoms.h"
+#include "nsLayoutAtoms.h"
 #include "nsIScriptContext.h"
 #include "nsIScriptContextOwner.h"
 #include "nsINameSpace.h"
@@ -430,7 +431,13 @@ nsXMLContentSink::AddAttributes(const nsIParserNode& aNode,
     nsIAtom* nameSpacePrefix = CutNameSpacePrefix(name);
     nsIAtom* nameAtom = NS_NewAtom(name);
     PRInt32 nameSpaceID = GetNameSpaceId(nameSpacePrefix);
-    if ((kNameSpaceID_None == nameSpaceID) && aIsHTML) {
+    if ((kNameSpaceID_XMLNS == nameSpaceID) && aIsHTML) {
+      NS_RELEASE(nameAtom);
+      name.Insert("xmlns:", 0);
+      nameAtom = NS_NewAtom(name);
+      nameSpaceID = kNameSpaceID_HTML;
+    }
+    else if ((kNameSpaceID_None == nameSpaceID) && aIsHTML) {
       nameSpaceID = kNameSpaceID_HTML;
     }
 
diff --git a/mozilla/layout/xml/tests/docbooktest.xml b/mozilla/layout/xml/tests/docbooktest.xml
index c51d434ff78..75a9fa8d089 100644
--- a/mozilla/layout/xml/tests/docbooktest.xml
+++ b/mozilla/layout/xml/tests/docbooktest.xml
@@ -6,6 +6,9 @@ Inc.</Title>
 <p xmlns="http://www.w3.org/TR/REC-html40" xmlns:h="http://www.w3.org/TR/REC-html40">
 <h:img src="flamer.gif"/>
 <img src="flamer.gif"/>
+<button>
+<h1>Some text</h1>
+</button>
 </p>
 <BookInfo> <BookBiblio> <Title>Demo Product Documentation</Title>
 <AuthorGroup><CorpAuthor>SoftQuad Inc.</CorpAuthor></AuthorGroup>