Update dummy.html

Author: streamcode9

pages/dummy.html

@@ -26,6 +26,7 @@ <h2>WebAssembly Greeting Demo</h2>
     try {
       return await WebAssembly.instantiateStreaming(res, imports);
     } catch {
+      alert('fallback');
       // Fallback if wrong MIME
       const bytes = await res.arrayBuffer();
       return await WebAssembly.instantiate(bytes, imports);