diff --git a/demo/client.ts b/demo/client.ts
index 1b3987bd..5202db76 100644
--- a/demo/client.ts
+++ b/demo/client.ts
@@ -454,7 +454,7 @@ function htmlSerializeButtonHandler(): void {
 
   // Deprecated, but the most supported for now.
   function listener(e: any) {
-    e.clipboardData.setData("text/plain", output);
+    e.clipboardData.setData("text/html", output);
     e.preventDefault();
   }
   document.addEventListener("copy", listener);