title: how to replace Head script using Greasemonkey code
body: <p>i want to replace "script.js" to "demo.js". anyone please help me</p>
  
  <pre><code>&lt;head&gt;
  
      &lt;script src="script.js" type="text/javascript" language="javaScript"&gt;&lt;/script&gt;     
  
  &lt;/head&gt;
  </code></pre>