JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <textarea id='prop_notes'></textarea>
</body>

CSS

textarea {
    height:300px;
    width:100%;
}

JavaScript

$(document).ready(function () {
    $("#prop_notes").on('dblclick', function () {
        var timestamp = '<?php echo $timestamp; ?>';
        var userid = '<?php echo $user_id; ?>';
        var username = '<?php echo $user_full_name; ?>';
        if ($('#prop_notes').val() == '') {
            $("#prop_notes").val("Timestamp: " + timestamp + "\nUser ID: " + userid + "\nUser: " + username);
        } else {
            $("#prop_notes").val($("#prop_notes").val() + "\n\n- - - - - - - - - - - - - - - - - - - -\n\nTimestamp: " + timestamp + "\nUser ID: " + userid + "\nUser: " + username);
        }
    });
});