Upgrade code from fckeditor page

Hello

I have a page configured with fckeditor with this code:

<script type="text/javascript" src="../Edt/fckeditor.js"></script>

<script type="text/javascript">
 window.onload=function()
 {
  var sBasePath = '../Edt/'
  var oFCKeditor = new FCKeditor( 'fTxt' ) ;
  
  oFCKeditor.BasePath = sBasePath ;
  oFCKeditor.Height = 500 ;
  //oFCKeditor.Value = 'This is some <strong>sample text<\/strong>. You are using <a href="http://www.fckeditor.net/">FCKeditor<\/a>.' ;
  oFCKeditor.ReplaceTextarea() ;
 }
</script>

I there a simple way to replace with an upgrade to CKeditor 4?  Someone could write it to me?

Thank you.

Valter.