title: Allow only one br in nl2br
body: <p>I let my members of my website to post some information about them in textarea. I use function <code>nl2br</code> to be it more prettier, smth like that:</p>
  
  <p><p></p>
  
  <pre><code>$text_of_area = nl2br($_POST['text_area_name']); //yeah, of course i use functions against xss, sql injection attacks
  
  mysql_query("..."); //here I insert a text
  </code></pre>
  
  <p><p></p>
  
  <p>But here is problem. I don't want to allow people to use more then one enter (br) allowed in text, so what can I do?</p>