Required Java,javascript,jquery,JQuery Mobile freelancer for Need Help with Javascript on Shopify Page job

Hi there, i have a shopify page which needs to calculate:
**** The number of characters on the longest line on a text area.****
This is then times by 8 or 12 to give the size of neon light.

This is the current Javascript code. Can't seem to use Keyup etc because external app is using the function?

$(function(){
var observer = new MutationObserver(function() {
updateWordCount();
} );
observer.observe(document.body, {
childList: true
} );



function updateWordCount(){
var currentLength = $('#pplr-4325256953910 textarea').val().length;
//console.log(currentLength);
$('.count2').html(currentLength*12);
}

} );

Skills & Expertise Required

Java javascript jquery JQuery Mobile