1 files changed, 9 insertions, 1 deletions
diff --git a/dom/base/EventSource.cpp b/dom/base/EventSource.cpp
index f70db487dd..def3c90ec0 100644
--- a/dom/base/EventSource.cpp
+++ b/dom/base/EventSource.cpp
@@ -568,7 +568,15 @@ nsresult EventSourceImpl::ParseURL(const nsAString& aURL) {
   NS_ENSURE_SUCCESS(rv, rv);
 
   nsCOMPtr<nsIURI> srcURI;
-  rv = NS_NewURI(getter_AddRefs(srcURI), aURL, nullptr, baseURI);
+  nsCOMPtr<Document> doc =
+      mIsMainThread ? GetEventSource()->GetDocumentIfCurrent() : nullptr;
+  if (doc) {
+    rv = NS_NewURI(getter_AddRefs(srcURI), aURL, doc->GetDocumentCharacterSet(),
+                   baseURI);
+  } else {
+    rv = NS_NewURI(getter_AddRefs(srcURI), aURL, nullptr, baseURI);
+  }
+
   NS_ENSURE_SUCCESS(rv, NS_ERROR_DOM_SYNTAX_ERR);
 
   nsAutoString origin;