title: How to use XPath to check if <Success /> node exists
body: <p>I am working with PHP and XPath connecting to a remote XML based API. A sample response from the server is as this one below.</p>
  
  <pre><code>    &lt;OTA_PingRS&gt;
          &lt;Success /&gt;
          &lt;EchoData&gt;This is some test data&lt;/EchoData&gt;
      &lt;/OTA_PingRS&gt;
  </code></pre>
  
  <p>You can see there is no starting tag <code>&lt;Success&gt;</code> so how do I search for the existance of <code>&lt;Success /&gt;</code> using Xpath?</p>
  
  <p>Thanks
  Simon</p>