diff --git a/README.md b/README.md
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/README.md
diff --git a/main.js b/main.js
new file mode 100644
index 0000000..e7d200f
--- /dev/null
+++ b/main.js
@@ -0,0 +1 @@
+window.alert('Hello, World');
diff --git a/manifest.json b/manifest.json
new file mode 100644
index 0000000..fe1cfaa
--- /dev/null
+++ b/manifest.json
@@ -0,0 +1,10 @@
+{
+   "name": "sample extension",
+   "description": "sample code",
+   "manifest_version": 2,
+   "content_scripts": [ {
+      "matches": [ "http://*/*", "https://*/*" ],
+      "js": [ "main.js" ]
+   } ],
+   "version": "1.0.0.0"
+}