diff --git a/src/components/script/dom/attr.rs b/src/components/script/dom/attr.rs
index e7e13853087..9ecf068774e 100644
--- a/src/components/script/dom/attr.rs
+++ b/src/components/script/dom/attr.rs
@@ -89,7 +89,10 @@ impl Attr {
     }
 
     pub fn GetNamespaceURI(&self) -> Option<DOMString> {
-        self.namespace.to_str().map(|s| s.to_owned())
+        match self.namespace.to_str() {
+            "" => None,
+            url => Some(url.to_owned()),
+        }
     }
 
     pub fn GetPrefix(&self) -> Option<DOMString> {
diff --git a/src/components/util/namespace.rs b/src/components/util/namespace.rs
index 354f95f69b2..ff9eda169c9 100644
--- a/src/components/util/namespace.rs
+++ b/src/components/util/namespace.rs
@@ -28,16 +28,16 @@ impl Namespace {
             ns => Other(ns.to_owned())
         }
     }
-    pub fn to_str<'a>(&'a self) -> Option<&'a str> {
+    pub fn to_str<'a>(&'a self) -> &'a str {
         match *self {
-            Null => None,
-            HTML => Some("http://www.w3.org/1999/xhtml"),
-            XML => Some("http://www.w3.org/XML/1998/namespace"),
-            XMLNS => Some("http://www.w3.org/2000/xmlns/"),
-            XLink => Some("http://www.w3.org/1999/xlink"),
-            SVG => Some("http://www.w3.org/2000/svg"),
-            MathML => Some("http://www.w3.org/1998/Math/MathML"),
-            Other(ref x) => Some(x.as_slice())
+            Null => "",
+            HTML => "http://www.w3.org/1999/xhtml",
+            XML => "http://www.w3.org/XML/1998/namespace",
+            XMLNS => "http://www.w3.org/2000/xmlns/",
+            XLink => "http://www.w3.org/1999/xlink",
+            SVG => "http://www.w3.org/2000/svg",
+            MathML => "http://www.w3.org/1998/Math/MathML",
+            Other(ref x) => x.as_slice()
         }
     }
 }