diff --git a/content/html/content/src/nsHTMLStyleElement.cpp b/content/html/content/src/nsHTMLStyleElement.cpp
index ae814ca7e97d..532e38f7df8c 100644
--- a/content/html/content/src/nsHTMLStyleElement.cpp
+++ b/content/html/content/src/nsHTMLStyleElement.cpp
@@ -353,7 +353,7 @@ nsHTMLStyleElement::GetStyleSheetURL(PRBool* aIsInline,
   if (*aIsInline) {
     return;
   }
-  if (mNodeInfo->NamespaceEquals(kNameSpaceID_HTML)) {
+  if (mNodeInfo->NamespaceEquals(kNameSpaceID_XHTML)) {
     // We stopped supporting <style src="..."> for XHTML as it is
     // non-standard.
     *aIsInline = PR_TRUE;