Date: 05/06/14 (Code WTF)    Keywords: html

горячие калифорнийские .... пишут:          

            // Try replacing both lowercase utf-8 and upper UTF-8 and similar combinations.

          // Covering all cases here.

          $html = str_replace('', '', $html);

          $html = str_replace('', '', $html);

          $html = str_replace('', '', $html);

          $html = str_replace('', '', $html);

Source: https://code-wtf.livejournal.com/220115.html