JSFiddle - React, Tailwind, and code Playground

HTML

<form id="target" action>
    <label>First Name:</label>
    <input type="text" id="fName" />
    <br /><br />
    <label>Last Name:</label>
    <input type="text" id="lName" /><br><br>
    <input type="submit" value="Submit"/>
    <br /><br />
</form>
<textarea id="message"></textarea>

JavaScript

$('form#target').submit(function(e) {
    e.preventDefault();
    var message, firstName, lastName;
    
    message = "Dear ";
    firstName = $('input#fName').val();
    lastName = $('input#lName').val();
    
    message += firstName + ' ';
    message += lastName + ',';
    $('textarea#message').text(message);
});