title: Retrieve data from html page using xpath and php
body: <p>I know there are similar question, but, trying to study PHP I met this error and I want understand why this occurs.</p>
  
  <pre><code>&lt;?php
      $url = 'http://aice.anie.it/quotazione-lme-rame/';
      echo "hello!\r\n";
      $html = new DOMDocument();
      @$html-&gt;loadHTML($url);
      $xpath = new DOMXPath($html);
      $nodelist = $xpath-&gt;query(".//*[@id='table33']/tbody/tr[2]/td[3]/b");
  
      foreach ($nodelist as $n) {
          echo $n-&gt;nodeValue . "\n";
      }
  ?&gt;
  </code></pre>
  
  <p>this prints just "hello!". I want to print the value extracted with the xpath, but the last echo doesn't do anything.</p>