Text Area: How to limit the lines of text based on a number on another field?

One more question. I have added a field to allow names of attendies, is there a way to add an error message in case the Number of attending field do not match with the names of attendies listed?

Unfortunately, I could not find a way to achieve this with JotForm, but you may implement such functionality with some JavaScript code, please note that JavaScript code is not allowed on the builder so you will need to get the source code of your form. 

Here are the links that will help you: 

https://www.jotform.com/help/104-How-to-get-the-Full-Source-Code-of-your-Form

https://stackoverflow.com/questions/556767/limiting-number-of-lines-in-textarea?rq=1 

I hope this helps.