diff --git a/dlls/msxml3/attribute.c b/dlls/msxml3/attribute.c
index 76c690e1ad0..a6cd8a12abc 100644
--- a/dlls/msxml3/attribute.c
+++ b/dlls/msxml3/attribute.c
@@ -543,10 +543,11 @@ static HRESULT WINAPI domattr_get_namespaceURI(
     IXMLDOMAttribute *iface,
     BSTR* p)
 {
-    static const WCHAR w3xmlns[] = { 'h','t','t','p',':','/','/', 'w','w','w','.','w','3','.',
-        'o','r','g','/','2','0','0','0','/','x','m','l','n','s','/',0 };
     domattr *This = impl_from_IXMLDOMAttribute( iface );
     xmlNsPtr ns = This->node.node->ns;
+    BSTR nodename, pfx;
+    BOOL is6, isdefault;
+    HRESULT hr;
 
     TRACE("(%p)->(%p)\n", This, p);
 
@@ -554,23 +555,36 @@ static HRESULT WINAPI domattr_get_namespaceURI(
         return E_INVALIDARG;
 
     *p = NULL;
+    nodename = NULL;
+    hr = IXMLDOMAttribute_get_nodeName(iface, &nodename);
+    if (FAILED(hr))
+        return hr;
 
-    if (ns)
+    pfx = NULL;
+    hr = IXMLDOMAttribute_get_prefix(iface, &pfx);
+    if (FAILED(hr))
     {
-        /* special case for default namespace definition */
-        if (xmlStrEqual(This->node.node->name, xmlns))
-            *p = bstr_from_xmlChar(xmlns);
-        else if (xmlStrEqual(ns->prefix, xmlns))
-        {
-            if (xmldoc_version(This->node.node->doc) == MSXML6)
-                *p = SysAllocString(w3xmlns);
-            else
-                *p = SysAllocStringLen(NULL, 0);
-        }
-        else if (ns->href)
-            *p = bstr_from_xmlChar(ns->href);
+        SysFreeString(nodename);
+        return hr;
     }
 
+    is6 = xmldoc_version(This->node.node->doc) == MSXML6;
+    isdefault = !wcscmp(nodename, L"xmlns");
+    if (isdefault || (pfx && !wcscmp(L"xmlns", pfx)))
+    {
+        if (is6)
+            *p = SysAllocString(L"http://www.w3.org/2000/xmlns/");
+        else if (!ns || !isdefault)
+            *p = SysAllocStringLen(NULL, 0);
+        else
+            *p = SysAllocString(L"xmlns");
+    }
+    else if (ns && ns->href)
+        *p = bstr_from_xmlChar(ns->href);
+
+    SysFreeString(nodename);
+    SysFreeString(pfx);
+
     TRACE("uri: %s\n", debugstr_w(*p));
 
     return *p ? S_OK : S_FALSE;
diff --git a/dlls/msxml3/tests/domdoc.c b/dlls/msxml3/tests/domdoc.c
index 7997106bbd0..ce2e7e655eb 100644
--- a/dlls/msxml3/tests/domdoc.c
+++ b/dlls/msxml3/tests/domdoc.c
@@ -13677,7 +13677,6 @@ static void test_namespaces_as_attributes(void)
         const char *uris[3];
         const char *texts[3];
         const char *xmls[3];
-        BOOL todo;
     };
     static const struct test tests[] = {
         {
@@ -13718,7 +13717,6 @@ static void test_namespaces_as_attributes(void)
             { "" },                 /* namespaceURI */
             { "nshref" },           /* text */
             { "xmlns=\"nshref\"" }, /* xml */
-            TRUE,                   /* todo */
         },
         /* no properties or namespaces */
         {
@@ -13802,7 +13800,6 @@ static void test_namespaces_as_attributes(void)
                 hr = IXMLDOMNode_get_namespaceURI(item, &str);
                 if (test->uris[i])
                 {
-                    todo_wine_if(test->todo)
                     ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
                     if (test->prefixes[i] && !strcmp(test->prefixes[i], "xmlns"))
                         ok(!SysStringLen(str), "got %s\n", wine_dbgstr_w(str));
diff --git a/dlls/msxml4/tests/domdoc.c b/dlls/msxml4/tests/domdoc.c
index 3c5c34f3cb7..1a3a663d359 100644
--- a/dlls/msxml4/tests/domdoc.c
+++ b/dlls/msxml4/tests/domdoc.c
@@ -166,7 +166,6 @@ static void test_namespaces_as_attributes(void)
         const WCHAR *uris[3];
         const WCHAR *texts[3];
         const WCHAR *xmls[3];
-        BOOL todo;
     };
     static const struct test tests[] =
     {
@@ -208,7 +207,6 @@ static void test_namespaces_as_attributes(void)
             { L"" },                    /* namespaceURI */
             { L"nshref" },              /* text */
             { L"xmlns=\"nshref\"" },    /* xml */
-            TRUE,                       /* todo */
         },
         /* no properties or namespaces */
         {
@@ -289,13 +287,11 @@ static void test_namespaces_as_attributes(void)
             hr = IXMLDOMNode_get_namespaceURI(item, &str);
             if (test->uris[i])
             {
-                todo_wine_if(test->todo) {
                 ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
                 if (test->prefixes[i] && !lstrcmpW(test->prefixes[i], L"xmlns"))
                     ok(!lstrcmpW(str, L""), "got %s\n", wine_dbgstr_w(str));
                 else
                     ok(!lstrcmpW(str, test->uris[i]), "got %s\n", wine_dbgstr_w(str));
-                }
                 SysFreeString(str);
             }
             else
diff --git a/dlls/msxml6/tests/domdoc.c b/dlls/msxml6/tests/domdoc.c
index b36b8e6510a..d451d0dd50c 100644
--- a/dlls/msxml6/tests/domdoc.c
+++ b/dlls/msxml6/tests/domdoc.c
@@ -59,12 +59,11 @@ struct attrtest_t {
     const WCHAR *uri;
     const WCHAR *prefix;
     const WCHAR *href;
-    BOOL todo;
 };
 
 static struct attrtest_t attrtests[] = {
-    { L"xmlns", L"http://www.w3.org/2000/xmlns/", NULL, L"http://www.w3.org/2000/xmlns/", TRUE },
-    { L"xmlns", L"nondefaulturi", NULL, L"http://www.w3.org/2000/xmlns/", TRUE },
+    { L"xmlns", L"http://www.w3.org/2000/xmlns/", NULL, L"http://www.w3.org/2000/xmlns/" },
+    { L"xmlns", L"nondefaulturi", NULL, L"http://www.w3.org/2000/xmlns/" },
     { L"c", L"http://www.w3.org/2000/xmlns/", NULL, L"http://www.w3.org/2000/xmlns/" },
     { L"c", L"nsref1", NULL, L"nsref1" },
     { L"ns:c", L"nsref1", L"ns", L"nsref1" },
@@ -113,7 +112,6 @@ static void test_create_attribute(void)
         str = NULL;
         hr = IXMLDOMNode_get_namespaceURI(node, &str);
         ok(hr == S_OK, "%d: unexpected hr %#lx\n", i, hr);
-        todo_wine_if(ptr->todo)
         ok(!lstrcmpW(str, _bstr_(ptr->href)) ||
             broken(!ptr->prefix && !lstrcmpW(str, L"xmlns")), /* win7 msxml6 */
             "%d: got uri %s, expected %s\n", i, wine_dbgstr_w(str), wine_dbgstr_w(ptr->href));
@@ -171,7 +169,6 @@ static void test_namespaces_as_attributes(void)
         const WCHAR *uris[3];
         const WCHAR *texts[3];
         const WCHAR *xmls[3];
-        BOOL todo;
     };
     static const struct test tests[] =
     {
@@ -213,7 +210,6 @@ static void test_namespaces_as_attributes(void)
             { L"http://www.w3.org/2000/xmlns/" },   /* namespaceURI */
             { L"nshref" },                          /* text */
             { L"xmlns=\"nshref\"" },                /* xml */
-            TRUE,                                   /* todo */
         },
         /* no properties or namespaces */
         {
@@ -273,10 +269,8 @@ static void test_namespaces_as_attributes(void)
             hr = IXMLDOMNode_get_prefix(item, &str);
             if (test->prefixes[i])
             {
-                todo_wine_if(test->todo) {
                 ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
                 ok(!lstrcmpW(str, test->prefixes[i]), "got %s\n", wine_dbgstr_w(str));
-                }
                 SysFreeString(str);
             }
             else
@@ -292,14 +286,12 @@ static void test_namespaces_as_attributes(void)
             hr = IXMLDOMNode_get_namespaceURI(item, &str);
             if (test->uris[i])
             {
-                todo_wine_if(test->todo) {
                 ok(hr == S_OK, "Unexpected hr %#lx.\n", hr);
                 if (test->prefixes[i] && !lstrcmpW(test->prefixes[i], L"xmlns"))
                     ok(!lstrcmpW(str, L"http://www.w3.org/2000/xmlns/"),
                                  "got %s\n", wine_dbgstr_w(str));
                 else
                     ok(!lstrcmpW(str, test->uris[i]), "got %s\n", wine_dbgstr_w(str));
-                }
                 SysFreeString(str);
             }
             else