diff --git a/share/jupyterhub/templates/login.html b/share/jupyterhub/templates/login.html
index 8c8e83bd..23165308 100644
--- a/share/jupyterhub/templates/login.html
+++ b/share/jupyterhub/templates/login.html
@@ -91,7 +91,7 @@
 {% block script %}
   {{ super() }}
   <script>
-    if (window.location.protocol === "http:") {
+    if (!window.isSecureContext) {
       // unhide http warning
       var warning = document.getElementById('insecure-login-warning');
       warning.className = warning.className.replace(/\bhidden\b/, '');