JSFiddle - React, Tailwind, and code Playground

HTML

<h3>Success handler</h3>
<div class="feedback-box-success"></div>
<h4>Log (success)</h4>
<ol id="log_success"></ol>
<hr>
<h3>Complete handler</h3>
<div class="feedback-box-complete"></div>
<h4>Log (complete)</h4>
<ol id="log_complete"></ol>

JavaScript

function get_fb_success(){
    $('#log_success').append('<li>get_fb() ran</li>');
    var feedback = $.ajax({
        type: "POST",
        url: "feedback.php",
        async: false
    }).success(function(){
        setTimeout(function(){get_fb_success();}, 10000);
    }).responseText;

    $('div.feedback-box-success').html('success feedback');
}


function get_fb_complete(){
    $('#log_complete').append('<li>get_fb() ran</li>');
    var feedback = $.ajax({
        type: "POST",
        url: "feedback.php",
        async: false
    }).complete(function(){
        setTimeout(function(){get_fb_complete();}, 10000);
    }).responseText;

    $('div.feedback-box-complete').html('complete feedback');
}

$(function(){
    get_fb_success();
    get_fb_complete();
});