diff --git a/src/browser/get-document-protocol.js b/src/browser/get-document-protocol.js
index 3b24042a7..9308c582c 100644
--- a/src/browser/get-document-protocol.js
+++ b/src/browser/get-document-protocol.js
@@ -3,7 +3,7 @@
 module.exports = getDocumentProtocol;
 
 function getDocumentProtocol() {
-  return 'https';
+  return 'https:';
   var protocol = window.document.location.protocol;
 
   // when in `file:` mode (local html file), default to `http:`