diff --git a/.github/workflows/cypress-tests.yml b/.github/workflows/cypress-tests.yml
index fc2c6007eae..50b71368c74 100644
--- a/.github/workflows/cypress-tests.yml
+++ b/.github/workflows/cypress-tests.yml
@@ -17,11 +17,11 @@ name: Cypress E2E Tests
 
 on:
   push:
-    branches: [ "master" ]
+    branches: [ "master", "2.x" ]
     paths:
       - 'storm-webapp/**'
   pull_request:
-    branches: [ "master" ]
+    branches: [ "master", "2.x" ]
     paths:
       - 'storm-webapp/**'
   workflow_dispatch:
diff --git a/storm-webapp/src/main/java/org/apache/storm/daemon/ui/WEB-INF/flux.html b/storm-webapp/src/main/java/org/apache/storm/daemon/ui/WEB-INF/flux.html
index ad676c17a78..9d869992135 100644
--- a/storm-webapp/src/main/java/org/apache/storm/daemon/ui/WEB-INF/flux.html
+++ b/storm-webapp/src/main/java/org/apache/storm/daemon/ui/WEB-INF/flux.html
@@ -70,7 +70,14 @@
 
       function parseAndRender() {
         var input = document.getElementById('taInput').value;
-        var doc = jsyaml.load(input);
+        var doc;
+        try {
+          doc = jsyaml.load(input);
+        } catch (e) {
+          // js-yaml >=5 throws on empty/comment-only input instead of
+          // returning undefined (see migrate_v4_to_v5); treat as no document.
+          return;
+        }
 	if(doc==null){
 	   return;
 	}