diff --git a/mozilla/content/base/src/nsDOMAttribute.cpp b/mozilla/content/base/src/nsDOMAttribute.cpp
index 7bd7ba106d8..05f315b7d8b 100644
--- a/mozilla/content/base/src/nsDOMAttribute.cpp
+++ b/mozilla/content/base/src/nsDOMAttribute.cpp
@@ -22,6 +22,7 @@
 #include "nsIContent.h"
 #include "nsIDOMScriptObjectFactory.h"
 #include "nsITextContent.h"
+#include "nsINameSpaceManager.h"
 
 static NS_DEFINE_IID(kIDOMAttrIID, NS_IDOMATTR_IID);
 static NS_DEFINE_IID(kIDOMAttributePrivateIID, NS_IDOMATTRIBUTEPRIVATE_IID);
@@ -158,6 +159,9 @@ nsDOMAttribute::GetValue(nsString& aValue)
     nsresult attrResult;
 
     mContent->ParseAttributeString(mName, nameAtom, nameSpaceID);
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     attrResult = mContent->GetAttribute(nameSpaceID, nameAtom, mValue);
     if (NS_CONTENT_ATTR_NOT_THERE == attrResult) {
       mValue.Truncate();
@@ -177,6 +181,9 @@ nsDOMAttribute::SetValue(const nsString& aValue)
     PRInt32 nameSpaceID;
 
     mContent->ParseAttributeString(mName, nameAtom, nameSpaceID);
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     result = mContent->SetAttribute(nameSpaceID, nameAtom, aValue, PR_TRUE);
     NS_IF_RELEASE(nameAtom);
   }
@@ -199,6 +206,9 @@ nsDOMAttribute::GetSpecified(PRBool* aSpecified)
     PRInt32 nameSpaceID;
 
     mContent->ParseAttributeString(mName, nameAtom, nameSpaceID);    
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     attrResult = mContent->GetAttribute(nameSpaceID, nameAtom, value);
     NS_IF_RELEASE(nameAtom);
     if (NS_CONTENT_ATTR_HAS_VALUE == attrResult) {
@@ -369,6 +379,9 @@ nsDOMAttribute::CloneNode(PRBool aDeep, nsIDOMNode** aReturn)
     PRInt32 nameSpaceID;
   
     mContent->ParseAttributeString(mName, nameAtom, nameSpaceID);    
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     mContent->GetAttribute(nameSpaceID, nameAtom, value);
     newAttr = new nsDOMAttribute(nsnull, mName, value); 
   }
diff --git a/mozilla/content/base/src/nsDOMAttributeMap.cpp b/mozilla/content/base/src/nsDOMAttributeMap.cpp
index 325b411eca4..4949b821353 100644
--- a/mozilla/content/base/src/nsDOMAttributeMap.cpp
+++ b/mozilla/content/base/src/nsDOMAttributeMap.cpp
@@ -241,6 +241,9 @@ nsDOMAttributeMap::GetNamedItem(const nsString &aAttrName,
     nsAutoString normalizedName;
 
     mContent->ParseAttributeString(aAttrName, nameAtom, nameSpaceID);
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     GetNormalizedName(nameSpaceID, nameAtom, normalizedName);
     result = GetNamedItemCommon(normalizedName, 
                                 nameSpaceID, 
@@ -279,6 +282,9 @@ nsDOMAttributeMap::SetNamedItem(nsIDOMNode *aNode, nsIDOMNode **aReturn)
         // Get normalized attribute name
         attribute->GetName(name);
         mContent->ParseAttributeString(name, nameAtom, nameSpaceID);
+        if (kNameSpaceID_Unknown == nameSpaceID) {
+          nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+        }
         GetNormalizedName(nameSpaceID, nameAtom, name);
         name.ToCString(buf, sizeof(buf));
         result = GetNamedItemCommon(name, nameSpaceID, nameAtom, &oldAttribute);
@@ -361,6 +367,9 @@ nsDOMAttributeMap::RemoveNamedItem(const nsString& aName, nsIDOMNode** aReturn)
       nsAutoString name;
 
       mContent->ParseAttributeString(aName, nameAtom, nameSpaceID);
+      if (kNameSpaceID_Unknown == nameSpaceID) {
+        nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+      }
       GetNormalizedName(nameSpaceID, nameAtom, name);
       name.ToCString(buf, sizeof(buf));
       result = GetNamedItemCommon(name, nameSpaceID, nameAtom, &attribute);
diff --git a/mozilla/content/base/src/nsDocument.cpp b/mozilla/content/base/src/nsDocument.cpp
index 97dd15e47ed..0f1c50b4ac6 100644
--- a/mozilla/content/base/src/nsDocument.cpp
+++ b/mozilla/content/base/src/nsDocument.cpp
@@ -47,11 +47,11 @@
 #include "nsIDOMDOMImplementation.h"
 #include "nsGenericElement.h"
 
-#include "nsCSSPropIDs.h"
-#include "nsCSSProps.h"
+//#include "nsCSSPropIDs.h"
+//#include "nsCSSProps.h"
 #include "nsICSSStyleSheet.h"
-#include "nsICSSStyleRule.h"
-#include "nsICSSDeclaration.h"
+//#include "nsICSSStyleRule.h"
+//#include "nsICSSDeclaration.h"
 
 #include "nsITextContent.h"
 #include "nsXIFConverter.h"
diff --git a/mozilla/content/base/src/nsGenericElement.cpp b/mozilla/content/base/src/nsGenericElement.cpp
index 37c5206f6a5..b02cad23c01 100644
--- a/mozilla/content/base/src/nsGenericElement.cpp
+++ b/mozilla/content/base/src/nsGenericElement.cpp
@@ -394,6 +394,9 @@ nsGenericElement::GetAttribute(const nsString& aName, nsString& aReturn)
   PRInt32 nameSpaceID;
 
   mContent->ParseAttributeString(aName, nameAtom, nameSpaceID);
+  if (kNameSpaceID_Unknown == nameSpaceID) {
+    nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+  }
   mContent->GetAttribute(nameSpaceID, nameAtom, aReturn);
   NS_RELEASE(nameAtom);
 
@@ -409,6 +412,9 @@ nsGenericElement::SetAttribute(const nsString& aName,
   nsresult result = NS_OK;
 
   mContent->ParseAttributeString(aName, nameAtom, nameSpaceID);
+  if (kNameSpaceID_Unknown == nameSpaceID) {
+    nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+  }
   result = mContent->SetAttribute(nameSpaceID, nameAtom, aValue, PR_TRUE);
   NS_RELEASE(nameAtom);
 
@@ -423,6 +429,9 @@ nsGenericElement::RemoveAttribute(const nsString& aName)
   nsresult result = NS_OK;
 
   mContent->ParseAttributeString(aName, nameAtom, nameSpaceID);
+  if (kNameSpaceID_Unknown == nameSpaceID) {
+    nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+  }
   result = mContent->UnsetAttribute(nameSpaceID, nameAtom, PR_TRUE);
   NS_RELEASE(nameAtom);
 
diff --git a/mozilla/content/xul/content/src/nsXULAttributes.cpp b/mozilla/content/xul/content/src/nsXULAttributes.cpp
index 7c5b91e172c..b0cdad1bc5c 100644
--- a/mozilla/content/xul/content/src/nsXULAttributes.cpp
+++ b/mozilla/content/xul/content/src/nsXULAttributes.cpp
@@ -442,6 +442,9 @@ nsXULAttributes::GetNamedItem(const nsString& aName, nsIDOMNode** aReturn)
     if (NS_FAILED(rv = mContent->ParseAttributeString(aName, name, nameSpaceID)))
         return rv;
 
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     // XXX doing this instead of calling mContent->GetAttribute() will
     // make it a lot harder to lazily instantiate properties from the
     // graph. The problem is, how else do we get the named item?
diff --git a/mozilla/content/xul/content/src/nsXULElement.cpp b/mozilla/content/xul/content/src/nsXULElement.cpp
index dd3c3a89d85..ff20e0cb584 100644
--- a/mozilla/content/xul/content/src/nsXULElement.cpp
+++ b/mozilla/content/xul/content/src/nsXULElement.cpp
@@ -879,6 +879,9 @@ RDFElementImpl::GetAttribute(const nsString& aName, nsString& aReturn)
         NS_WARNING("unable to parse attribute name");
         return rv;
     }
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
 
     GetAttribute(nameSpaceID, nameAtom, aReturn);
     NS_RELEASE(nameAtom);
diff --git a/mozilla/content/xul/templates/src/nsXULTemplateBuilder.cpp b/mozilla/content/xul/templates/src/nsXULTemplateBuilder.cpp
index 39d216828d7..13e3055e443 100644
--- a/mozilla/content/xul/templates/src/nsXULTemplateBuilder.cpp
+++ b/mozilla/content/xul/templates/src/nsXULTemplateBuilder.cpp
@@ -1643,6 +1643,9 @@ RDFGenericBuilderImpl::OnSetAttribute(nsIDOMElement* aElement, const nsString& a
     }
 
     // If we get here, it's a "vanilla" property: push its value into the graph.
+    if (kNameSpaceID_Unknown == attrNameSpaceID) {
+      attrNameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     nsCOMPtr<nsIRDFResource> property;
     if (NS_FAILED(rv = GetResource(attrNameSpaceID, attrNameAtom, getter_AddRefs(property)))) {
         NS_ERROR("unable to construct resource");
@@ -1746,6 +1749,9 @@ RDFGenericBuilderImpl::OnRemoveAttribute(nsIDOMElement* aElement, const nsString
         // It's a "vanilla" property: push its value into the graph.
 
         nsCOMPtr<nsIRDFResource> property;
+        if (kNameSpaceID_Unknown == attrNameSpaceID) {
+          attrNameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+        }
         if (NS_FAILED(rv = GetResource(attrNameSpaceID, attrNameAtom, getter_AddRefs(property)))) {
             NS_ERROR("unable to construct resource");
             return rv;
diff --git a/mozilla/layout/base/src/nsDOMAttribute.cpp b/mozilla/layout/base/src/nsDOMAttribute.cpp
index 7bd7ba106d8..05f315b7d8b 100644
--- a/mozilla/layout/base/src/nsDOMAttribute.cpp
+++ b/mozilla/layout/base/src/nsDOMAttribute.cpp
@@ -22,6 +22,7 @@
 #include "nsIContent.h"
 #include "nsIDOMScriptObjectFactory.h"
 #include "nsITextContent.h"
+#include "nsINameSpaceManager.h"
 
 static NS_DEFINE_IID(kIDOMAttrIID, NS_IDOMATTR_IID);
 static NS_DEFINE_IID(kIDOMAttributePrivateIID, NS_IDOMATTRIBUTEPRIVATE_IID);
@@ -158,6 +159,9 @@ nsDOMAttribute::GetValue(nsString& aValue)
     nsresult attrResult;
 
     mContent->ParseAttributeString(mName, nameAtom, nameSpaceID);
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     attrResult = mContent->GetAttribute(nameSpaceID, nameAtom, mValue);
     if (NS_CONTENT_ATTR_NOT_THERE == attrResult) {
       mValue.Truncate();
@@ -177,6 +181,9 @@ nsDOMAttribute::SetValue(const nsString& aValue)
     PRInt32 nameSpaceID;
 
     mContent->ParseAttributeString(mName, nameAtom, nameSpaceID);
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     result = mContent->SetAttribute(nameSpaceID, nameAtom, aValue, PR_TRUE);
     NS_IF_RELEASE(nameAtom);
   }
@@ -199,6 +206,9 @@ nsDOMAttribute::GetSpecified(PRBool* aSpecified)
     PRInt32 nameSpaceID;
 
     mContent->ParseAttributeString(mName, nameAtom, nameSpaceID);    
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     attrResult = mContent->GetAttribute(nameSpaceID, nameAtom, value);
     NS_IF_RELEASE(nameAtom);
     if (NS_CONTENT_ATTR_HAS_VALUE == attrResult) {
@@ -369,6 +379,9 @@ nsDOMAttribute::CloneNode(PRBool aDeep, nsIDOMNode** aReturn)
     PRInt32 nameSpaceID;
   
     mContent->ParseAttributeString(mName, nameAtom, nameSpaceID);    
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     mContent->GetAttribute(nameSpaceID, nameAtom, value);
     newAttr = new nsDOMAttribute(nsnull, mName, value); 
   }
diff --git a/mozilla/layout/base/src/nsDOMAttributeMap.cpp b/mozilla/layout/base/src/nsDOMAttributeMap.cpp
index 325b411eca4..4949b821353 100644
--- a/mozilla/layout/base/src/nsDOMAttributeMap.cpp
+++ b/mozilla/layout/base/src/nsDOMAttributeMap.cpp
@@ -241,6 +241,9 @@ nsDOMAttributeMap::GetNamedItem(const nsString &aAttrName,
     nsAutoString normalizedName;
 
     mContent->ParseAttributeString(aAttrName, nameAtom, nameSpaceID);
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     GetNormalizedName(nameSpaceID, nameAtom, normalizedName);
     result = GetNamedItemCommon(normalizedName, 
                                 nameSpaceID, 
@@ -279,6 +282,9 @@ nsDOMAttributeMap::SetNamedItem(nsIDOMNode *aNode, nsIDOMNode **aReturn)
         // Get normalized attribute name
         attribute->GetName(name);
         mContent->ParseAttributeString(name, nameAtom, nameSpaceID);
+        if (kNameSpaceID_Unknown == nameSpaceID) {
+          nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+        }
         GetNormalizedName(nameSpaceID, nameAtom, name);
         name.ToCString(buf, sizeof(buf));
         result = GetNamedItemCommon(name, nameSpaceID, nameAtom, &oldAttribute);
@@ -361,6 +367,9 @@ nsDOMAttributeMap::RemoveNamedItem(const nsString& aName, nsIDOMNode** aReturn)
       nsAutoString name;
 
       mContent->ParseAttributeString(aName, nameAtom, nameSpaceID);
+      if (kNameSpaceID_Unknown == nameSpaceID) {
+        nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+      }
       GetNormalizedName(nameSpaceID, nameAtom, name);
       name.ToCString(buf, sizeof(buf));
       result = GetNamedItemCommon(name, nameSpaceID, nameAtom, &attribute);
diff --git a/mozilla/layout/base/src/nsDocument.cpp b/mozilla/layout/base/src/nsDocument.cpp
index 97dd15e47ed..0f1c50b4ac6 100644
--- a/mozilla/layout/base/src/nsDocument.cpp
+++ b/mozilla/layout/base/src/nsDocument.cpp
@@ -47,11 +47,11 @@
 #include "nsIDOMDOMImplementation.h"
 #include "nsGenericElement.h"
 
-#include "nsCSSPropIDs.h"
-#include "nsCSSProps.h"
+//#include "nsCSSPropIDs.h"
+//#include "nsCSSProps.h"
 #include "nsICSSStyleSheet.h"
-#include "nsICSSStyleRule.h"
-#include "nsICSSDeclaration.h"
+//#include "nsICSSStyleRule.h"
+//#include "nsICSSDeclaration.h"
 
 #include "nsITextContent.h"
 #include "nsXIFConverter.h"
diff --git a/mozilla/layout/base/src/nsGenericElement.cpp b/mozilla/layout/base/src/nsGenericElement.cpp
index 37c5206f6a5..b02cad23c01 100644
--- a/mozilla/layout/base/src/nsGenericElement.cpp
+++ b/mozilla/layout/base/src/nsGenericElement.cpp
@@ -394,6 +394,9 @@ nsGenericElement::GetAttribute(const nsString& aName, nsString& aReturn)
   PRInt32 nameSpaceID;
 
   mContent->ParseAttributeString(aName, nameAtom, nameSpaceID);
+  if (kNameSpaceID_Unknown == nameSpaceID) {
+    nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+  }
   mContent->GetAttribute(nameSpaceID, nameAtom, aReturn);
   NS_RELEASE(nameAtom);
 
@@ -409,6 +412,9 @@ nsGenericElement::SetAttribute(const nsString& aName,
   nsresult result = NS_OK;
 
   mContent->ParseAttributeString(aName, nameAtom, nameSpaceID);
+  if (kNameSpaceID_Unknown == nameSpaceID) {
+    nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+  }
   result = mContent->SetAttribute(nameSpaceID, nameAtom, aValue, PR_TRUE);
   NS_RELEASE(nameAtom);
 
@@ -423,6 +429,9 @@ nsGenericElement::RemoveAttribute(const nsString& aName)
   nsresult result = NS_OK;
 
   mContent->ParseAttributeString(aName, nameAtom, nameSpaceID);
+  if (kNameSpaceID_Unknown == nameSpaceID) {
+    nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+  }
   result = mContent->UnsetAttribute(nameSpaceID, nameAtom, PR_TRUE);
   NS_RELEASE(nameAtom);
 
diff --git a/mozilla/rdf/base/src/nsRDFContentSink.cpp b/mozilla/rdf/base/src/nsRDFContentSink.cpp
index 8a70d3c2f08..352cb76efff 100644
--- a/mozilla/rdf/base/src/nsRDFContentSink.cpp
+++ b/mozilla/rdf/base/src/nsRDFContentSink.cpp
@@ -1073,6 +1073,9 @@ RDFContentSinkImpl::AddProperties(const nsIParserNode& aNode,
         nsRDFParserUtils::StripAndConvert(v);
 
         nsAutoString k;
+        if (kNameSpaceID_Unknown == nameSpaceID) {
+          nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+        }
         GetNameSpaceURI(nameSpaceID, k);
         k.Append(attr->GetUnicode());
 
diff --git a/mozilla/rdf/content/src/nsRDFElement.cpp b/mozilla/rdf/content/src/nsRDFElement.cpp
index dd3c3a89d85..ff20e0cb584 100644
--- a/mozilla/rdf/content/src/nsRDFElement.cpp
+++ b/mozilla/rdf/content/src/nsRDFElement.cpp
@@ -879,6 +879,9 @@ RDFElementImpl::GetAttribute(const nsString& aName, nsString& aReturn)
         NS_WARNING("unable to parse attribute name");
         return rv;
     }
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
 
     GetAttribute(nameSpaceID, nameAtom, aReturn);
     NS_RELEASE(nameAtom);
diff --git a/mozilla/rdf/content/src/nsRDFGenericBuilder.cpp b/mozilla/rdf/content/src/nsRDFGenericBuilder.cpp
index 39d216828d7..13e3055e443 100644
--- a/mozilla/rdf/content/src/nsRDFGenericBuilder.cpp
+++ b/mozilla/rdf/content/src/nsRDFGenericBuilder.cpp
@@ -1643,6 +1643,9 @@ RDFGenericBuilderImpl::OnSetAttribute(nsIDOMElement* aElement, const nsString& a
     }
 
     // If we get here, it's a "vanilla" property: push its value into the graph.
+    if (kNameSpaceID_Unknown == attrNameSpaceID) {
+      attrNameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     nsCOMPtr<nsIRDFResource> property;
     if (NS_FAILED(rv = GetResource(attrNameSpaceID, attrNameAtom, getter_AddRefs(property)))) {
         NS_ERROR("unable to construct resource");
@@ -1746,6 +1749,9 @@ RDFGenericBuilderImpl::OnRemoveAttribute(nsIDOMElement* aElement, const nsString
         // It's a "vanilla" property: push its value into the graph.
 
         nsCOMPtr<nsIRDFResource> property;
+        if (kNameSpaceID_Unknown == attrNameSpaceID) {
+          attrNameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+        }
         if (NS_FAILED(rv = GetResource(attrNameSpaceID, attrNameAtom, getter_AddRefs(property)))) {
             NS_ERROR("unable to construct resource");
             return rv;
diff --git a/mozilla/rdf/content/src/nsRDFXULBuilder.cpp b/mozilla/rdf/content/src/nsRDFXULBuilder.cpp
index 5f62adb2880..8dc7c9412fc 100644
--- a/mozilla/rdf/content/src/nsRDFXULBuilder.cpp
+++ b/mozilla/rdf/content/src/nsRDFXULBuilder.cpp
@@ -1508,6 +1508,9 @@ RDFXULBuilderImpl::OnSetAttribute(nsIDOMElement* aElement, const nsString& aName
     // the RDF graph to update. So, build an RDF resource from the
     // property name...
     nsCOMPtr<nsIRDFResource> property;
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     if (NS_FAILED(rv = GetResource(nameSpaceID, nameAtom, getter_AddRefs(property)))) {
         NS_ERROR("unable to construct resource");
         return rv;
@@ -1580,6 +1583,9 @@ RDFXULBuilderImpl::OnRemoveAttribute(nsIDOMElement* aElement, const nsString& aN
         }
 
         nsCOMPtr<nsIRDFResource> property;
+        if (kNameSpaceID_Unknown == nameSpaceID) {
+          nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+        }
         if (NS_FAILED(rv = GetResource(nameSpaceID, nameAtom, getter_AddRefs(property)))) {
             NS_ERROR("unable to construct resource");
             return rv;
diff --git a/mozilla/rdf/content/src/nsXULAttributes.cpp b/mozilla/rdf/content/src/nsXULAttributes.cpp
index 7c5b91e172c..b0cdad1bc5c 100644
--- a/mozilla/rdf/content/src/nsXULAttributes.cpp
+++ b/mozilla/rdf/content/src/nsXULAttributes.cpp
@@ -442,6 +442,9 @@ nsXULAttributes::GetNamedItem(const nsString& aName, nsIDOMNode** aReturn)
     if (NS_FAILED(rv = mContent->ParseAttributeString(aName, name, nameSpaceID)))
         return rv;
 
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     // XXX doing this instead of calling mContent->GetAttribute() will
     // make it a lot harder to lazily instantiate properties from the
     // graph. The problem is, how else do we get the named item?
diff --git a/mozilla/rdf/content/src/nsXULElement.cpp b/mozilla/rdf/content/src/nsXULElement.cpp
index dd3c3a89d85..ff20e0cb584 100644
--- a/mozilla/rdf/content/src/nsXULElement.cpp
+++ b/mozilla/rdf/content/src/nsXULElement.cpp
@@ -879,6 +879,9 @@ RDFElementImpl::GetAttribute(const nsString& aName, nsString& aReturn)
         NS_WARNING("unable to parse attribute name");
         return rv;
     }
+    if (kNameSpaceID_Unknown == nameSpaceID) {
+      nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
 
     GetAttribute(nameSpaceID, nameAtom, aReturn);
     NS_RELEASE(nameAtom);
diff --git a/mozilla/rdf/content/src/nsXULTemplateBuilder.cpp b/mozilla/rdf/content/src/nsXULTemplateBuilder.cpp
index 39d216828d7..13e3055e443 100644
--- a/mozilla/rdf/content/src/nsXULTemplateBuilder.cpp
+++ b/mozilla/rdf/content/src/nsXULTemplateBuilder.cpp
@@ -1643,6 +1643,9 @@ RDFGenericBuilderImpl::OnSetAttribute(nsIDOMElement* aElement, const nsString& a
     }
 
     // If we get here, it's a "vanilla" property: push its value into the graph.
+    if (kNameSpaceID_Unknown == attrNameSpaceID) {
+      attrNameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+    }
     nsCOMPtr<nsIRDFResource> property;
     if (NS_FAILED(rv = GetResource(attrNameSpaceID, attrNameAtom, getter_AddRefs(property)))) {
         NS_ERROR("unable to construct resource");
@@ -1746,6 +1749,9 @@ RDFGenericBuilderImpl::OnRemoveAttribute(nsIDOMElement* aElement, const nsString
         // It's a "vanilla" property: push its value into the graph.
 
         nsCOMPtr<nsIRDFResource> property;
+        if (kNameSpaceID_Unknown == attrNameSpaceID) {
+          attrNameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+        }
         if (NS_FAILED(rv = GetResource(attrNameSpaceID, attrNameAtom, getter_AddRefs(property)))) {
             NS_ERROR("unable to construct resource");
             return rv;
diff --git a/mozilla/rdf/datasource/src/nsXULContentSink.cpp b/mozilla/rdf/datasource/src/nsXULContentSink.cpp
index 1bd8ea4ebcd..2efcdca0ecc 100644
--- a/mozilla/rdf/datasource/src/nsXULContentSink.cpp
+++ b/mozilla/rdf/datasource/src/nsXULContentSink.cpp
@@ -1188,6 +1188,9 @@ XULContentSinkImpl::AddAttributes(const nsIParserNode& aNode,
         nsIAtom* prefix = CutNameSpacePrefix(attr);
         if (prefix) {
             SplitQualifiedName(key, nameSpaceID, attr);
+            if (kNameSpaceID_Unknown == nameSpaceID) {
+              nameSpaceID = kNameSpaceID_None;  // ignore unknown prefix XXX is this correct?
+            }
             NS_RELEASE(prefix);
         }
         else {