Text box word count and error message

Hi All,

Any thoughts on how to add a script in Adobe Acrobat 2017 to a text box, which will perform and show a current word count from a required amount "Say 250 words", and if this is not achieved, then show a message box saying "Word count much exceed 250"

I have 4 text boxes on a form and need this to show in a field above each text box.

Thank you for any help provided