diff --git a/iframe.html b/iframe.html
new file mode 100644
index 0000000..61a670e
--- /dev/null
+++ b/iframe.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
+    <title>Document</title>
+  </head>
+  <body>
+    <h3>The message from the parent appears below:</h3>
+    <div id="message">Please send some message from the input above.</div>
+    <script>
+      window.addEventListener("message", function (event) {
+        document.querySelector("#message").innerText =
+          typeof event.data === "string"
+            ? event.data
+            : JSON.stringify(event.data);
+      });
+    </script>
+    <input style="margin-top: 1em" type="text" id="messageText" />
+    <button id="sendMessage">Send Message to Parent</button>
+    <script>
+      var button = document.querySelector("#sendMessage");
+      button.addEventListener("click", function () {
+        var message = document.querySelector("#messageText").value;
+        window.parent.postMessage(message, "*");
+      });
+    </script>
+  </body>
+</html>
