JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="results"></ul>

JavaScript

var el = $('#results');

$.ajax({
    type: "GET",
    url: '//httpbin.org/get',
    data : {
        'fp': 'test'
    },
    dataType : "JSON",
    success: function(response) {
        el.append('<li>DEBUG: visitor has been registered</li>');
    },
    error: function(jqXHR, textStatus, errorThrown) {
        el.append("<li>DEBUG jqXHR.responseText : " + jqXHR.responseText + "</li>");
        var response = jqXHR.responseText;

        el.append('<li>Failure!</li>');
        if(jqXHR.status&&jqXHR.status==400){
            // alert(jqXHR.responseText);
            var response = $.parseJSON(jqXHR.responseText);

            if (response) {
                 el.append("<li>DEBUG jqXHR.responseText : " + response.error + "</li>");
            } else {
                // This would mean an invalid response from the server - maybe the site went down or whatever...
                el.append('<li>DEBUG: Inside jqXHR.status : Something went wrong<li>');
            }
        } else {
            el.append("<li>DEBUG: Something went wrong</li>");
        }
    }
});