title: When to use Strip_tags and when to use htmlspecialchars()
body: <p>Every time I look at a code someone wrote, they either use </p>
  
  <pre><code>            $var = htmlspecialchars($var);
          $var = trim($var);
          $var = stripcslashes($var);
  </code></pre>
  
  <p>or just</p>
  
  <pre><code>strip_tags($var)
  </code></pre>
  
  <p>when to use the first and the second one?</p>