chrome/test/data/extensions/user_script_basic.user.js

// ==UserScript==
// @name My user script
// @version 2.2.2
// @namespace http://www.google.com
// @description Does totally awesome stuff.
// @include http://www.google.com/*
// @include http://www.yahoo.com/*
// @exclude *foo*
// @match http://www.google.com/*
// @exclude_match http://www.google.com/foo*
// ==/UserScript==

alert("Hello! This is my script.");