How to add exclusion tag to regex?

Question

Regular Expressions

Good day, dear experts.

There is such a code that cuts out comments from html code.

// remove HTML comments (not containing IE conditional comments).
    $this->_html = preg_replace_callback(
      '/<!--([\\s\\S]*?)-->/'
      ,array($this, '_commentCB')
      ,$this->_html);

How to add two tag cut exception to it - <!--noindex-->and<!--/noindex-->

Answer 1

// remove HTML comments (not containing IE conditional comments).
    $this->_html = preg_replace_callback(
      '#<!--(?!/?noindex)(.*?)-->#s'
      ,array($this, '_commentCB')
      ,$this->_html);