JSFiddle - React, Tailwind, and code Playground

HTML

<form id="form">
<textarea name="content" id="ta">Hi

Hello world</textarea>
</form>

<div id="val-length"></div>
<div id="serial-length"></div>

JavaScript

$(function() {
    var valLen = $("#ta").val().length
    var serializeLen = $("#form").serializeArray()[0].value.length;
    
    $("#val-length").text(valLen);
    $("#serial-length").text(serializeLen);
});