diff --git a/testing/jsmaker-regression.rkt b/testing/jsmaker-regression.rkt
index 4bec1b4..6f0c629 100644
--- a/testing/jsmaker-regression.rkt
+++ b/testing/jsmaker-regression.rkt
@@ -1,6 +1,7 @@
 #lang racket/base
 
 (require racket/string
+         json
          "../main.rkt"
          "jsmaker-executors.rkt"
          "jsmaker-test-framework.rkt")
@@ -86,6 +87,37 @@
 (unless (not (regexp-match? #rx"__let_star_value" simple-let-star))
   (error 'jsmaker-regression "simple let* should not use tempvars, got: ~a" simple-let-star))
 
+(define webview-set-value-program
+  (let ([val "2026-05-28"])
+    (with-id->el/inject 'inp2 el
+      (if (or (= (js-dot el type) "checkbox")
+              (= (js-dot el type) "radio"))
+          (begin
+            (set! (js-dot el checked) (inject (if (eq? val #f) #f #t)))
+            #t)
+          (begin
+            (set! (js-dot el value) (inject val))
+            #t)))))
+
+(unless (not (regexp-match? #rx"return true;" webview-set-value-program))
+  (error 'jsmaker-regression
+         "top-level WebView-style js must not emit branch-level return true statements, got: ~a"
+         webview-set-value-program))
+
+(define webview-top-level-vm-smoke
+  (format #<<JS
+(() => {
+  if (typeof require !== 'function') return true;
+  const vm = require('vm');
+  const el = { type: 'text', value: '', checked: false };
+  const context = { document: { getElementById: (id) => el } };
+  vm.runInNewContext(~a, context);
+  return JSON.stringify([el.value, el.checked]) === ~a;
+})()
+JS
+          (jsexpr->string webview-set-value-program)
+          (jsexpr->string "[\"2026-05-28\",false]")))
+
 (define tests
   (list
    (js-expression-test 'if-zero (js/expression (if 0 1 2)) "1")
@@ -112,6 +144,9 @@
                        (js/expression (array (eval (list 1 2 3))
                                              (eval (string-append "a" "b"))))
                        "[[1,2,3],\"ab\"]")
+   (js-expression-test 'webview-top-level-script-vm
+                       webview-top-level-vm-smoke
+                       "true")
    (let ([x 10]
          [y 20])
      (js-expression-test 'runtime-eval-lexical-let