diff --git a/src/core/fetch/index.js b/src/core/fetch/index.js
index 0fac23bee..963a6bf0d 100644
--- a/src/core/fetch/index.js
+++ b/src/core/fetch/index.js
@@ -26,14 +26,14 @@ function isExternal(url) {
   );
   if (
     typeof match[1] === 'string' &&
-    match[1].length > 0 &&
+    match[1].length >= 0 &&
     match[1].toLowerCase() !== location.protocol
   ) {
     return true;
   }
   if (
     typeof match[2] === 'string' &&
-    match[2].length > 0 &&
+    match[2].length >= 0 &&
     match[2].replace(
       new RegExp(
         ':(' + { 'http:': 80, 'https:': 443 }[location.protocol] + ')?$'