JSFiddle - React, Tailwind, and code Playground

HTML

<form action="http://domain.com/index.php" method="post" name="contact_form"  id="contact_form">

            <input id="yourName" type="text" name="yourName" value="">                                
            <input id="yourEmail" type="text" name="yourEmail" value="">                                
            <input id="message" type="text" name="phoneNumber" value="">
            <input type="hidden" name="fromurl" value="http://www.google.com" id="fromurl">
            <textarea id="messagex" name="message" rows="10"></textarea>
            <button type="submit">Send</button>            </form>

JavaScript

(function ($) {
$("form#contact_form").submit(function (event) {
    var value1 = $("#fromurl").val();
    console.log(value1);
    //Use .html() to set the value of textarea
    var txtArea = $('#message').val();
    $('#message').val('');
    console.log(" input "+txtArea);
    $('#message').val(txtArea+value1);
    return false;
});
})(jQuery);