title: Chrome extension Page Action JS
body: <p>I'm trying to create an extension using this docs:
  <a href="http://code.google.com/chrome/extensions/content_scripts.html" rel="nofollow noreferrer">http://code.google.com/chrome/extensions/content_scripts.html</a></p>
  
  <p>I want a part of JS code to run when document is ready (loaded).</p>
  
  <p>This is my <strong>manifest.json</strong>:</p>
  
  <pre><code>{
      "name": "OwnExtension",
      "version": "0.1",
      "content_scripts": [
      {
          "matches": ["https://my.site.eu/*"],
          "css": ["styles.css"],
          "js": ["main.js"]
      }
      ]
  }
  </code></pre>
  
  <p>This is my <strong>main.js</strong>:</p>
  
  <pre><code>alert(10);
  </code></pre>
  
  <p>Am I doing sth wrong, that nothing happend when page <a href="https://my.site.eu/" rel="nofollow noreferrer">https://my.site.eu/</a> loaded in browser?</p>