diff --git a/dom/xslt/xslt/txExecutionState.cpp b/dom/xslt/xslt/txExecutionState.cpp
index 9c984e9cd2ad..a3cfddac1c62 100644
--- a/dom/xslt/xslt/txExecutionState.cpp
+++ b/dom/xslt/xslt/txExecutionState.cpp
@@ -395,7 +395,12 @@ txExecutionState::TemplateRule* txExecutionState::getCurrentTemplateRule() {
   return &mTemplateRules[mTemplateRules.Length() - 1];
 }
 
-txInstruction* txExecutionState::getNextInstruction() {
+mozilla::Result<txInstruction*, nsresult>
+txExecutionState::getNextInstruction() {
+  if (mStopProcessing) {
+    return mozilla::Err(NS_ERROR_FAILURE);
+  }
+
   txInstruction* instr = mNextInstruction;
   if (instr) {
     mNextInstruction = instr->mNext.get();
diff --git a/dom/xslt/xslt/txExecutionState.h b/dom/xslt/xslt/txExecutionState.h
index d8698802335e..7a314cf8a4b8 100644
--- a/dom/xslt/xslt/txExecutionState.h
+++ b/dom/xslt/xslt/txExecutionState.h
@@ -17,6 +17,7 @@
 #include "txStylesheet.h"
 #include "txXPathTreeWalker.h"
 #include "nsTArray.h"
+#include "mozilla/Result.h"
 
 class txAOutputHandlerFactory;
 class txAXMLEventHandler;
@@ -115,13 +116,14 @@ class txExecutionState : public txIMatchContext {
   }
 
   // state-modification functions
-  txInstruction* getNextInstruction();
+  mozilla::Result<txInstruction*, nsresult> getNextInstruction();
   nsresult runTemplate(txInstruction* aInstruction);
   nsresult runTemplate(txInstruction* aInstruction, txInstruction* aReturnTo);
   void gotoInstruction(txInstruction* aNext);
   void returnFromTemplate();
   nsresult bindVariable(const txExpandedName& aName, txAExprResult* aValue);
   void removeVariable(const txExpandedName& aName);
+  void stopProcessing() { mStopProcessing = true; }
 
   txAXMLEventHandler* mOutputHandler;
   txAXMLEventHandler* mResultHandler;
@@ -156,6 +158,7 @@ class txExecutionState : public txIMatchContext {
   txKeyHash mKeyHash;
   RefPtr<txResultRecycler> mRecycler;
   bool mDisableLoads;
+  bool mStopProcessing = false;
 
   static const int32_t kMaxRecursionDepth;
 };
diff --git a/dom/xslt/xslt/txMozillaXSLTProcessor.cpp b/dom/xslt/xslt/txMozillaXSLTProcessor.cpp
index c50a66a40201..6ce9932f8c80 100644
--- a/dom/xslt/xslt/txMozillaXSLTProcessor.cpp
+++ b/dom/xslt/xslt/txMozillaXSLTProcessor.cpp
@@ -538,6 +538,79 @@ already_AddRefed<Document> txMozillaXSLTProcessor::TransformToDocument(
   return doc.forget();
 }
 
+class XSLTProcessRequest final : public nsIRequest {
+ public:
+  explicit XSLTProcessRequest(txExecutionState* aState) : mState(aState) {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIREQUEST
+
+  void Done() { mState = nullptr; }
+
+ private:
+  ~XSLTProcessRequest() {}
+  txExecutionState* mState;
+};
+NS_IMPL_ISUPPORTS(XSLTProcessRequest, nsIRequest)
+
+NS_IMETHODIMP
+XSLTProcessRequest::GetName(nsACString& aResult) {
+  aResult.AssignLiteral("about:xslt-load-blocker");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XSLTProcessRequest::IsPending(bool* _retval) {
+  *_retval = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XSLTProcessRequest::GetStatus(nsresult* status) {
+  *status = NS_OK;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XSLTProcessRequest::Cancel(nsresult status) {
+  mState->stopProcessing();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XSLTProcessRequest::Suspend(void) { return NS_OK; }
+
+NS_IMETHODIMP
+XSLTProcessRequest::Resume(void) { return NS_OK; }
+
+NS_IMETHODIMP
+XSLTProcessRequest::GetLoadGroup(nsILoadGroup** aLoadGroup) {
+  *aLoadGroup = nullptr;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XSLTProcessRequest::SetLoadGroup(nsILoadGroup* aLoadGroup) { return NS_OK; }
+
+NS_IMETHODIMP
+XSLTProcessRequest::GetLoadFlags(nsLoadFlags* aLoadFlags) {
+  *aLoadFlags = nsIRequest::LOAD_NORMAL;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XSLTProcessRequest::SetLoadFlags(nsLoadFlags aLoadFlags) { return NS_OK; }
+
+NS_IMETHODIMP
+XSLTProcessRequest::GetTRRMode(nsIRequest::TRRMode* aTRRMode) {
+  return GetTRRModeImpl(aTRRMode);
+}
+
+NS_IMETHODIMP
+XSLTProcessRequest::SetTRRMode(nsIRequest::TRRMode aTRRMode) {
+  return SetTRRModeImpl(aTRRMode);
+}
+
 nsresult txMozillaXSLTProcessor::TransformToDoc(Document** aResult,
                                                 bool aCreateDataDocument) {
   UniquePtr<txXPathNode> sourceNode(
@@ -548,10 +621,29 @@ nsresult txMozillaXSLTProcessor::TransformToDoc(Document** aResult,
 
   txExecutionState es(mStylesheet, IsLoadDisabled());
 
+  Document* sourceDoc = mSource->OwnerDoc();
+  nsCOMPtr<nsILoadGroup> loadGroup = sourceDoc->GetDocumentLoadGroup();
+  if (!loadGroup) {
+    nsCOMPtr<nsPIDOMWindowInner> win = do_QueryInterface(mOwner);
+    if (win && win->IsCurrentInnerWindow()) {
+      Document* doc = win->GetDoc();
+      if (doc) {
+        loadGroup = doc->GetDocumentLoadGroup();
+      }
+    }
+
+    if (!loadGroup) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  RefPtr<XSLTProcessRequest> xsltProcessRequest = new XSLTProcessRequest(&es);
+  loadGroup->AddRequest(xsltProcessRequest, nullptr);
+
   // XXX Need to add error observers
 
   // If aResult is non-null, we're a data document
-  txToDocHandlerFactory handlerFactory(&es, mSource->OwnerDoc(), mObserver,
+  txToDocHandlerFactory handlerFactory(&es, sourceDoc, mObserver,
                                        aCreateDataDocument);
   es.mOutputHandlerFactory = &handlerFactory;
 
@@ -562,6 +654,9 @@ nsresult txMozillaXSLTProcessor::TransformToDoc(Document** aResult,
     rv = txXSLTProcessor::execute(es);
   }
 
+  xsltProcessRequest->Done();
+  loadGroup->RemoveRequest(xsltProcessRequest, nullptr, NS_OK);
+
   nsresult endRv = es.end(rv);
   if (NS_SUCCEEDED(rv)) {
     rv = endRv;
diff --git a/dom/xslt/xslt/txXSLTProcessor.cpp b/dom/xslt/xslt/txXSLTProcessor.cpp
index dfcdeb559534..bcf1a611088e 100644
--- a/dom/xslt/xslt/txXSLTProcessor.cpp
+++ b/dom/xslt/xslt/txXSLTProcessor.cpp
@@ -31,12 +31,20 @@ void txXSLTProcessor::shutdown() { txHandlerTable::shutdown(); }
 
 /* static */
 nsresult txXSLTProcessor::execute(txExecutionState& aEs) {
-  nsresult rv = NS_OK;
-  txInstruction* instr;
-  while ((instr = aEs.getNextInstruction())) {
-    rv = instr->execute(aEs);
-    NS_ENSURE_SUCCESS(rv, rv);
-  }
+  nsresult rv;
+  do {
+    mozilla::Result<txInstruction*, nsresult> result = aEs.getNextInstruction();
+    if (result.isErr()) {
+      return result.unwrapErr();
+    }
 
-  return NS_OK;
+    txInstruction* instr = result.unwrap();
+    if (!instr) {
+      return NS_OK;
+    }
+
+    rv = instr->execute(aEs);
+  } while (NS_SUCCEEDED(rv));
+
+  return rv;
 }