diff --git a/demo/SimpleText.mjs b/demo/SimpleText.mjs
index 562d517..dd898b3 100644
--- a/demo/SimpleText.mjs
+++ b/demo/SimpleText.mjs
@@ -1,6 +1,6 @@
 // @ts-check
 
-import { WebComponent } from "../src/WebComponent";
+import { WebComponent } from "../src/WebComponent.js";
 
 class SimpleText extends WebComponent {
   clickCallback() {