title: How to use "not" in XPath?
body: <p>I want to write something of the sort:</p>
  
  <pre><code>//a[not contains(@id, 'xx')]
  </code></pre>
  
  <p>(meaning all the links that there 'id' attribute doesn't contain the string 'xx')</p>
  
  <p>I can't find the right syntax.</p>