title: XPath wildcard in attribute value
body: <p>I have the following XPath to match attributes of the class span:</p>
  
  <pre><code>//span[@class='amount']
  </code></pre>
  
  <p>I want to match all elements that have the class attribute of "amount" but also may have other classes as well. I thought I could do this:</p>
  
  <pre><code>//span[@class='*amount*'] 
  </code></pre>
  
  <p>but that doesn't work...how can I do this?</p>