diff --git a/mozilla/content/base/src/nsDocument.cpp b/mozilla/content/base/src/nsDocument.cpp
index 614641057b6..b05d6e6e74c 100644
--- a/mozilla/content/base/src/nsDocument.cpp
+++ b/mozilla/content/base/src/nsDocument.cpp
@@ -99,6 +99,7 @@
 #include "nsIMultiPartChannel.h"
 #include "nsIRefreshURI.h"
 #include "nsIWebNavigation.h"
+#include "nsIConsoleService.h"
 
 #include "nsNetUtil.h"     // for NS_MakeAbsoluteURI
 
@@ -2301,6 +2302,22 @@ nsDocument::BeginLoad()
   NS_DOCUMENT_NOTIFY_OBSERVERS(BeginLoad, (this));
 }
 
+PRBool
+nsDocument::CheckGetElementByIdArg(const nsAString& aId)
+{
+  if (aId.IsEmpty()) {
+    nsCOMPtr<nsIConsoleService> consoleService
+      (do_GetService("@mozilla.org/consoleservice;1"));
+
+    if (consoleService) {
+      consoleService->LogStringMessage(NS_LITERAL_STRING(
+        "Empty string passed to getElementById().").get());
+    }
+    return PR_FALSE;
+  }
+  return PR_TRUE;
+}
+
 static void
 GetDocumentFromDocShellTreeItem(nsIDocShellTreeItem *aDocShell,
                                 nsIDocument **aDocument)
diff --git a/mozilla/content/base/src/nsDocument.h b/mozilla/content/base/src/nsDocument.h
index 7a5da61d2f7..635885766c7 100644
--- a/mozilla/content/base/src/nsDocument.h
+++ b/mozilla/content/base/src/nsDocument.h
@@ -643,6 +643,13 @@ public:
 
 protected:
 
+  /**
+   * Check that aId is not empty and log a message to the console
+   * service if it is.
+   * @returns PR_TRUE if aId looks correct, PR_FALSE otherwise.
+   */
+  static PRBool CheckGetElementByIdArg(const nsAString& aId);
+
   void DispatchContentLoadedEvents();
 
   void RetrieveRelevantHeaders(nsIChannel *aChannel);
diff --git a/mozilla/content/html/document/src/nsHTMLDocument.cpp b/mozilla/content/html/document/src/nsHTMLDocument.cpp
index b117b6c2d03..8fae66bb332 100644
--- a/mozilla/content/html/document/src/nsHTMLDocument.cpp
+++ b/mozilla/content/html/document/src/nsHTMLDocument.cpp
@@ -2475,10 +2475,7 @@ nsHTMLDocument::GetElementById(const nsAString& aElementId,
         return GetElementById(aElementId, aReturn);
       }
 
-      NS_ASSERTION(!aElementId.IsEmpty(),
-                   "getElementById(\"\") called, fix caller?");
-
-      if (mRootContent && !aElementId.IsEmpty()) {
+      if (mRootContent && CheckGetElementByIdArg(aElementId)) {
         e = nsContentUtils::MatchElementId(mRootContent, idAtom);
       }
     }
diff --git a/mozilla/content/xml/document/src/nsXMLDocument.cpp b/mozilla/content/xml/document/src/nsXMLDocument.cpp
index b3ef892d03c..e92acbb2ccb 100644
--- a/mozilla/content/xml/document/src/nsXMLDocument.cpp
+++ b/mozilla/content/xml/document/src/nsXMLDocument.cpp
@@ -673,8 +673,7 @@ nsXMLDocument::GetElementById(const nsAString& aElementId,
   NS_ENSURE_ARG_POINTER(aReturn);
   *aReturn = nsnull;
 
-  NS_ASSERTION(!aElementId.IsEmpty(), "getElementById(\"\"), fix caller?");
-  if (aElementId.IsEmpty())
+  if (!CheckGetElementByIdArg(aElementId))
     return NS_OK;
 
   // If we tried to load a document and something went wrong, we might not have
diff --git a/mozilla/content/xul/document/src/nsXULDocument.cpp b/mozilla/content/xul/document/src/nsXULDocument.cpp
index ba874080611..b13ed39bebd 100644
--- a/mozilla/content/xul/document/src/nsXULDocument.cpp
+++ b/mozilla/content/xul/document/src/nsXULDocument.cpp
@@ -1616,9 +1616,8 @@ nsXULDocument::GetElementById(const nsAString& aId,
     NS_ENSURE_ARG_POINTER(aReturn);
     *aReturn = nsnull;
 
-    NS_ASSERTION(!aId.IsEmpty(),"getElementById(\"\"), fix caller?");
-    if (aId.IsEmpty())
-      return NS_OK;
+    if (!CheckGetElementByIdArg(aId))
+        return NS_OK;
 
     nsresult rv;