Untitled

<script type="text/javascript">document.write('Hello, world!')</script>

{
  "name": "Hello World!",
  "description": "My first Chrome App.",
  "version": "0.1",
  "manifest_version": 2,
  "app": {
    "background": {
      "scripts": ["background.js"]
    }
  },
  "sandbox": {
              "pages": [ "window.html" ]
  },
  "icons": { "16": "calculator-16.png", "128": "calculator-128.png" }
}

<!DOCTYPE html>
<html>
  <head>
    <title>Hello, world</title>
  </head>
  <body>
    <script type='text/javascript'>
      document.write("Hello, world!");
    </script>
  </body>
</html>