diff --git a/browser/app.js b/browser/app.js
new file mode 100644
index 0000000..d923310
--- /dev/null
+++ b/browser/app.js
@@ -0,0 +1,31 @@
+import { hi2js } from '../transpiler.js';
+
+document.addEventListener('DOMContentLoaded', () => {
+    const hiInput = document.getElementById('hi-input');
+    const jsOutput = document.getElementById('js-output');
+
+    const transpile = () => {
+        const hiCode = hiInput.value;
+        try {
+            const jsCode = hi2js(hiCode);
+            jsOutput.value = jsCode;
+            jsOutput.style.color = '#333';
+        } catch (e) {
+            jsOutput.value = `Error: ${e.message}`;
+            jsOutput.style.color = 'red';
+        }
+    };
+
+    hiInput.addEventListener('input', transpile);
+
+    hiInput.value = `// Welcome, Master.
+message: "Hello from the browser!"
+_(message)
+
+// Try changing the value
+count: 10
+count = count + 5
+_("The new count is", count)
+`;
+    transpile();
+});