Pen Settings



CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. If you link to another Pen, it will include the CSS from that Pen. If the preprocessor matches, it will attempt to combine them before processing.

+ add another resource


Babel is required to process package imports. If you need a different preprocessor remove all packages first.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource


Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

Editor Settings

Code Indentation

Want to change your Syntax Highlighting theme, Fonts and more?

Visit your global Editor Settings.

HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.


              <h1>Switchin' It Up</h1>
    <select id="js-select-endpoint">
      <option value="users">Users</option>
      <option value="posts">Posts</option>

    <select id="js-select-id">
      <option value="1">1</option>
      <option value="2">2</option>
      <option value="3">3</option>
      <option value="4">4</option>
      <option value="5">5</option>
      <option value="6">6</option>
      <option value="7">7</option>
      <option value="8">8</option>
    <pre id="js-response-box">


              table {
  padding: 14px;


              'use strict';

// Helper Method
const ENDPOINT = 'users',
    ROOT     = '';

const makeRequest = function makeRequest(path, item) {
return new Promise(function(resolve, reject) {
  // Assumes jQuery
  path ? (path = '/' + path) : path = '/';
  item ? (item = '/' + item) : item = '/';
  const url = ROOT + path + item;
    .done(function (data) {
    .fail(function () {
// Code goes here
const select    = document.getElementById('js-select-endpoint'),
    id_select = document.getElementById('js-select-id'),
    response_box = document.getElementById('js-response-box');

// STREAM of button clicks on ENDPOINT selection
const endpoint_stream = 
  Rx.Observable.fromEvent(select, 'click').
    map(event  =>
    map(target => (target.options[target.selectedIndex].text.toLowerCase()));

const id_stream = 
  Rx.Observable.fromEvent(id_select, 'click').
    map(event  =>
    map(target => (target.options[target.selectedIndex].text.toLowerCase()));
const request_stream  = 
  // To wait until BOTH fields get updated, use zip:
    // Emits ARRAY: First element is from endpoint_stream, second is from id_stream
    map(data => makeRequest(data[0], data[1]))
    // Only hit server for DIFFERENT requests
    // Take only the last selections made every second
    // Listen to the most RECENT selection
    .subscribe(response => {
      response_box.innerHTML = JSON.stringify(response, null, 2);