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

You're using npm packages, so we've auto-selected Babel for you here, which we require to process imports and make it all work. If you need to use a different JavaScript preprocessor, remove the packages in the npm tab.

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

Use npm Packages

We can make npm packages available for you to use in your JavaScript. We use webpack to prepare them and make them available to import. We'll also process your JavaScript with Babel.

⚠️ This feature can only be used by logged in users.

Code Indentation


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.

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.

              <button id="open-modal" type="button">Show me the modal</button>

<dialog id="demo-modal">
  <h3 class="modal-header">A native modal dialog box</h3>
  <div class="modal-body">
    <p>Finally, HTML has a native dialog box element! This is fantastic.</p>
    <p>And a polyfill makes this usable today.</p>
  <footer class="modal-footer">
    <button id="like-it" type="button">I like it</button>
    <button id="love-it" type="button">I love it</button>
  <button id="close" class="close" type="button">&times;</button>

<p><code>returnValue</code>: <span id="return-value"></span></p>


<p> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Phasellus porttitor porttitor interdum. Vivamus vehicula nibh sit amet sapien varius hendrerit. Suspendisse ac lobortis mauris. Praesent tincidunt, risus nec pulvinar ullamcorper, ante erat luctus ante, eu suscipit elit purus sit amet turpis. In hac habitasse platea dictumst. Nulla lobortis libero non pulvinar tempus. Nulla tempor luctus sapien faucibus efficitur. Curabitur maximus nibh id sapien facilisis, vitae ultricies sem convallis. Nulla fermentum eget diam et finibus. Sed efficitur justo sed mollis ultrices. Sed pharetra dapibus nisi, non venenatis purus bibendum at. Integer risus mauris, faucibus non efficitur nec, viverra in mauris.</p>

<p>In lobortis arcu ac lobortis pulvinar. Aenean libero tellus, cursus id tortor non, iaculis dapibus diam. Nullam id nisi odio. Vivamus pellentesque lacinia turpis, eu eleifend justo posuere vel. Nulla pharetra nec justo eu facilisis. Vivamus sollicitudin, est ut varius eleifend, justo metus ultrices dui, ut scelerisque nisi odio vel est. Pellentesque nec tortor tristique, tempor velit at, lobortis augue. Nunc nunc neque, accumsan a placerat accumsan, rutrum sit amet turpis.</p>


<p>See my <a href="https://keithjgrant.com/posts/2018/meet-the-new-dialog-element/">&lt;dialog&gt; element write-up</a> for more details.</p>
              $blue-3: hsl(211, 57%, 25%);
$blue-4: hsl(211, 39%, 44%);
$blue-5: hsl(211, 51%, 65%);
$blue-7: hsl(211, 90%, 93%);
$blue-rich: hsl(211, 65%, 48%);

dialog {
  padding: 0;
  border: 0;
  border-radius: 0.6rem;
  box-shadow: 0 0 1em black;
/* native backdrop */
dialog::backdrop {
  background-color: rgba(0, 0, 0, 0.4);
/* polyfill backdrop */
dialog + .backdrop {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  background-color: rgba(0, 0, 0, 0.4);
dialog[open] {
  animation: slide-up 0.4s ease-out;

/* The following styles are for older browsers when using
   the polyfill. These aren’t necessary for Chrome/Firefox. */
dialog {
  display: none;
  position: absolute;
  margin: 0 auto; /* should center it, but not working in Safari */
  max-width: 80vw;
  background-color: white;
dialog[open] {
  display: block;

/* prettying things up a bit */
.close {
  position: absolute;
  top: 0.2em;
  right: 0.2em;
  padding: 0.3em;
  line-height: 0.6;
  background-color: transparent;
  border: 0;
  font-size: 2em;
.modal-footer {
  padding: 1em;

.modal-header {
  margin: 0;
  padding-bottom: 0.6em;
  background-color: $blue-7;
  border-top-left-radius: 0.6rem;
  border-top-right-radius: 0.6rem;
  border-bottom: 1px solid $blue-5;

.modal-footer {
  border-top: 1px solid $blue-5;

/* misc page styles -- not important for demo */
body {
  margin: 1em;

:first-child {
  margin-top: 0;

:last-child {
  margin-bottom: 0;

button {
  padding: 0.4em 1em 0.2em;
  font-family: Glober, Helvetica, sans-serif;

@keyframes slide-up {
  0% {
    opacity: 0;
    transform: translate(0, 15px);
  100% {
    opacity: 1;
    transform: translate(0, 0);
              const modal = document.getElementById('demo-modal');
const open = document.getElementById('open-modal');
const close = document.getElementById('close');
const likeIt = document.getElementById('like-it');
const loveIt = document.getElementById('love-it');
const returnSpan = document.getElementById('return-value');

open.addEventListener('click', () => {

likeIt.addEventListener('click', () => {
  modal.close('Like it');

loveIt.addEventListener('click', () => {
  modal.close('Love it');

close.addEventListener('click', () => {

modal.addEventListener('cancel', () => {

// close when clicking on backdrop
modal.addEventListener('click', (event) => {
  if (event.target === modal) {

// display returnValue
modal.addEventListener('close', () => {
  returnSpan.innerHTML = modal.returnValue;
🕑 One or more of the npm packages you are using needs to be built. You're the first person to ever need it! We're building it right now and your preview will start updating again when it's ready.