--- a/content/base/public/nsDeprecatedOperationList.h
+++ b/content/base/public/nsDeprecatedOperationList.h
@@ -34,8 +34,9 @@ DEPRECATED_OPERATION(GetSetUserData)
 DEPRECATED_OPERATION(MozGetAsFile)
 DEPRECATED_OPERATION(UseOfCaptureEvents)
 DEPRECATED_OPERATION(UseOfReleaseEvents)
 DEPRECATED_OPERATION(UseOfDOM3LoadMethod)
 DEPRECATED_OPERATION(ShowModalDialog)
 DEPRECATED_OPERATION(Window_Content)
 DEPRECATED_OPERATION(SyncXMLHttpRequest)
 DEPRECATED_OPERATION(DataContainerEvent)
+DEPRECATED_OPERATION(SendAsBinary)

--- a/content/base/src/nsXMLHttpRequest.cpp
+++ b/content/base/src/nsXMLHttpRequest.cpp
@@ -2256,16 +2256,20 @@ nsXMLHttpRequest::SendAsBinary(const nsA
                                ErrorResult& aRv)
 {
   char *data = static_cast<char*>(NS_Alloc(aBody.Length() + 1));
   if (!data) {
     aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
     return;
   }
 
+  if (GetOwner() && GetOwner()->GetExtantDoc()) {
+    GetOwner()->GetExtantDoc()->WarnOnceAbout(nsIDocument::eSendAsBinary);
+  }
+
   nsAString::const_iterator iter, end;
   aBody.BeginReading(iter);
   aBody.EndReading(end);
   char *p = data;
   while (iter != end) {
     if (*iter & 0xFF00) {
       NS_Free(data);
       aRv.Throw(NS_ERROR_DOM_INVALID_CHARACTER_ERR);

--- a/dom/locales/en-US/chrome/dom/dom.properties
+++ b/dom/locales/en-US/chrome/dom/dom.properties
@@ -141,8 +141,10 @@ UseOfDOM3LoadMethodWarning=Use of docume
 ShowModalDialogWarning=Use of window.showModalDialog() is deprecated. Use window.open() instead. For more help https://developer.mozilla.org/en-US/docs/Web/API/Window.open
 # LOCALIZATION NOTE: Do not translate "window._content" or "window.content"
 Window_ContentWarning=window._content is deprecated.  Please use window.content instead.
 # LOCALIZATION NOTE: Do not translate "XMLHttpRequest"
 SyncXMLHttpRequestWarning=Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help http://xhr.spec.whatwg.org/
 ImplicitMetaViewportTagFallback=No meta-viewport tag found. Please explicitly specify one to prevent unexpected behavioural changes in future versions. For more help https://developer.mozilla.org/en/docs/Mozilla/Mobile/Viewport_meta_tag
 # LOCALIZATION NOTE: Do not translate "DataContainerEvent" or "CustomEvent"
 DataContainerEventWarning=Use of DataContainerEvent is deprecated. Use CustomEvent instead.
+# LOCALIZATION NOTE: Do not translate "sendAsBinary" or "send(Blob data)"
+SendAsBinaryWarning=The non-standard sendAsBinary method is deprecated and will soon be removed. Use the standard send(Blob data) method instead.