Dynamic Stamp - Text Wrapping with JavaScript

I'm building a custom pdf for my organization to use on its documents. I was able to give it fields for things like name, title and date. But they would like me to field to enter a short description or sentence. The issue I'm running into is while users can input long strings it becomes cut off once they reach the end of the text box. I know I need to give it a wrapping function to drop the text down to show the full user input but I have a very rudimentary understanding of JavaScript as I'm learning as I go and could use some help.

I applied my current code to show what I'm working with.

var cAsk = "Enter Narrative" ;
var cTitle = "Narrative";

if(stampState == 'applying')
{​​​​
var cMsg = app.response(cAsk, cTitle);
event.value = cMsg;
}​​​​