cssAudio - Activefile-genericCSS - ActiveGeneric - ActiveHTML - ActiveImage - ActiveJS - ActiveSVG - ActiveText - Activefile-genericVideo - ActiveLovehtmlicon-new-collectionicon-personicon-teamlog-outoctocatpop-outspinnerstartv

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.

              .foo {
  margin: 60px auto;
  width: 80%;

h1, label {
  font-family: 'Arvo', serif;
  color: white;

@media screen and (min-width: 500px) {
  .foo {
    width: 40%;

select {
  outline: none;
              // App
var App = React.createClass({
  /*setting state*/
  getInitialState: function() {
    return {
      bgColor: "teal"
  /*changes state*/
  handleColorChange: function (color) {
    // when we set state directly, react doesn't know
    // about it. that's why we use setState
    this.setState({ bgColor: color });
  /*for the lifecycle methods*/
  updateBackgroundColor: function () {
    var body = document.querySelector('body')
    body.style.background = this.state.bgColor
  /*lifecycle methods*/
  componentDidMount: function () { 
  componentDidUpdate: function () { 
  render: function() {
    return (
    /* by calling the title here on the component, we can access this.props on header */
      <div className="foo">
        <h1>Hello, World!</h1>
        <label>What color?
          <ColorPicker value={this.state.bgColor} onColorChange={this.handleColorChange}/>

// ColorPicker component
var ColorPicker = React.createClass({
  propTypes: {
    value: React.PropTypes.string.isRequired,
    onColorChange: React.PropTypes.func
  handleChange: function(e) {
    var color = e.target.value
    // If whoever rendered us (the ColorPicker) is interested
    // when the color changes, let them know
    if (this.props.onColorChange)
  render: function() {
    return (
      <select value={this.props.value} onChange={this.handleChange}>
        <option value="orangered">orangered</option>
        <option value="teal">teal</option>
        <option value="orange">orange</option>
        <option value="indigo">indigo</option>
        <option value="red">red</option>

React.render(<App/>, document.querySelector('#main'));
🕑 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.
Loading ..................