(Urgent need help) Mouse event on CKEditor

I would like to know whether I can use the mouseup or mousedown event during I doing something in my textarea which bundler wit ckeditor?

I tried something like this

 CKEDITOR.instances.textEditorTextArea.on('mouseup', function() { 
  alert("haha");
});

but it is not responding... may i know why.. I need solution fast.. because i need to apply in my project..

thank you for read this..