fix: make parseUrl helper always have a protocl (#4673)

Fixes #3100.

src/js/utils/url.js

@@ -81,6 +81,10 @@ export const parseUrl = function(url) {
     details.host = details.host.replace(/:443$/, '');
   }
 
+  if (!details.protocol) {
+    details.protocol = window.location.protocol;
+  }
+
   if (addToBody) {
     document.body.removeChild(div);
   }