move ES6 feature detection from home1.css to home1.js

Combine the two inline script blocks into a single try/catch
using new Function() so old browsers fail gracefully.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

groups/home/bootstrap5/home1.css

@@ -608,43 +608,6 @@
   });
 </script>
 
-<!-- If browser is pre-ES6, show a warning-->
-<script>
-  window.isES6 = false;
-</script>
-<script>
-  <!-- test ES6 functionality -->
-  // Arrow functions support
-  () => {};
-
-  // Class support
-  class __ES6FeatureDetectionTest {}
-
-  // Object initializer property and method shorthands
-  let es6a = true;
-  let es6b = {
-    es6a,
-    es6c() {
-      return true;
-    },
-    es6d: [1, 2, 3],
-  };
-
-  // Object destructuring
-  let { es6c, es6d } = es6b;
-
-  // Spread operator
-  let es6e = [...es6d, 4];
-
-  // ternary operator
-  let es6f = es6a ? "ternary" : "no ternary";
-
-  // nullish coalescing
-  es6a ??= 10;
-
-  window.isES6 = true;
-</script>
-
 <script type="text/javascript">
   window.onload = function () {
     <!-- display the error message if feature detection flags old browser -->

groups/home/bootstrap5/home1.js

@@ -1,3 +1,38 @@
+// ES6 feature detection
+(function () {
+  window.isES6 = false;
+  try {
+    new Function([
+      "// Arrow functions",
+      "() => {};",
+      "",
+      "// Class support",
+      "class __ES6FeatureDetectionTest {}",
+      "",
+      "// Object initializer property and method shorthands",
+      "let es6a = true;",
+      "let es6b = {",
+      "  es6a,",
+      "  es6c() { return true; },",
+      "  es6d: [1, 2, 3],",
+      "};",
+      "",
+      "// Object destructuring",
+      "let { es6c, es6d } = es6b;",
+      "",
+      "// Spread operator",
+      "let es6e = [...es6d, 4];",
+      "",
+      "// Ternary operator",
+      "let es6f = es6a ? 'ternary' : 'no ternary';",
+      "",
+      "// Nullish coalescing",
+      "es6a ??= 10;",
+    ].join("\n"))();
+    window.isES6 = true;
+  } catch (e) {}
+})();
+
 const hamburgerComponent = {
   template: `<div class="bigger-fancy-text">
     <i v-bind:class="item.icon" aria-hidden="true"></i>