Pen Settings

HTML

About HTML Preprocessors

HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

Learn more · Versions

Adding Classes

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. So you don't have access to higher-up elements like the <html> tag. If you want to add classes there that can affect the whole document, this is the place to do it.

About the <head>

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. If you need things in the <head> of the document, put that code here.

!
Insecure Resource

The resource you are linking to is using the 'http' protocol, which may not work when the browser is using https.

CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

Learn more · Versions

CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.

We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).

Add External Stylesheets/Pens

Any URLs added here will be added as <link>s in order, and before the CSS in the editor. You can use the CSS from another Pen by using its URL and the proper URL extension.

Powered by Algolia
About External Resources

You can apply CSS to your Pen from any stylesheet on the web. Just put a URL to it here and we'll apply it, in the order you have them, before the CSS in the Pen itself.

You can also link to another Pen here (use the .css URL Extension) and we'll pull the CSS from that Pen and include it. If it's using a matching preprocessor, use the appropriate URL Extension and we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

Learn more

+ add another resource

JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

Learn more · Versions

Babel includes JSX processing.

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.

Powered by Algolia
About External Resources

You can apply a script from anywhere on the web to your Pen. Just put a URL to it here and we'll add it, in the order you have them, before the JavaScript in the Pen itself.

If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.

You can also link to another Pen here, and we'll pull the JavaScript from that Pen and include it. If it's using a matching preprocessor, we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.

Learn more

+ add another resource

Packages

Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

Powered by Algolia
About Packages

Using packages here is powered by esm.sh, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ESM usage.

All packages are different, so refer to their docs for how they work.

If you're using React / ReactDOM, make sure to turn on Babel for the JSX processing.

Behavior

Auto Save

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.

Format on Save

If enabled, your code will be formatted when you actively save your Pen. Note: your code becomes un-folded during formatting.

Editor Settings

Code Indentation

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

Visit your global Editor Settings.

HTML 

              
                .form-wrapper
  .search-form
  form
      .form-group
        .input-group(multiselect)
          label Select your Location
          select(name='eventLocations[]', multiple)
            option(selected='', value='') All
            optgroup(label='California')
              option(value='6431') Berkeley
              option(value='6453') Los Angeles
              option(value='6473') San Francisco
              option(value='6577') Santa Barbara
            optgroup(label='Colorado')
              option(value='6442') Denver
            optgroup(label='District of Columbia (DC)')
              option(value='6486') District of Columbia (DC)
            optgroup(label='Florida')
              option(value='6460') Miami
            optgroup(label='Illinois')
              option(value='6437') Chicago
            optgroup(label='Louisiana')
              option(value='6465') New Orleans
            optgroup(label='Massachusetts')
              option(value='6433') Boston
              option(value='10342') Martha's Vineyard
            optgroup(label='Michigan')
              option(value='6424') Ann Arbor
              option(value='6445') Detroit
              option(value='7166') East Lansing
            optgroup(label='Minnesota')
              option(value='6481') Twin Cities
            optgroup(label='New York')
              option(value='65') New York City
            optgroup(label='North Carolina')
              option(value='6427') Asheville
            optgroup(label='Oregon')
              option(value='66') Portland
            optgroup(label='Pennsylvania')
              option(value='6469') Philadelphia
              option(value='6470') Pittsburgh
            optgroup(label='Texas')
              option(value='6451') Houston
            optgroup(label='Vermont')
              option(value='6435') Burlington
            optgroup(label='Washington')
              option(value='6477') Seattle
            optgroup(label='Wisconsin')
              option(value='6456') Madison
              option(value='6461') Milwaukee
            optgroup(label='Australia')
              option(value='63') Melbourne
              option(value='64') Sydney
            optgroup(label='Ireland')
              option(value='6447') Dublin
      .form-group
        .input-group
          label Type of Event
          select(name='typesOfEvents')
            option(selected='', value='') All
            option(value='52') Mainstage
            option(value='53') StorySLAM
            option(value='54') GrandSLAM
            option(value='55') Special Events
            option(value='56') Education
            option(value='57') Community
        .input-group
          label Date
          select(name='eventDate')
            option(selected='', value='') All
            optgroup(label='2016')
              option(value='201606') June
              option(value='201607') July
              option(value='201608') August
              option(value='201609') September
              option(value='201610') October
              option(value='201611') November
              option(value='201612') December
      .form-group
        input.btn.dark.centered(type='submit', value='Find Events')
!

CSS 

              
                accent = #c9e0dc
ltestgrey = #DDDEDF
ltgrey = #999999
navy = #323870
greyBlack = #161414

html
  font-size 12px
body
  background-image linear-gradient(top left, navy 0%, black 100%)
  font-family 'Helvetica', sans-serif
  display flex
  flex-direction column
  justify-content center
  min-height 100vh
  font-weight 200
[multiselect]
  position relative
  &:after
    display none
  select
    display none
.form-wrapper
  margin 0 auto
  background accent
  box-shadow 0 0 20px rgba(greyBlack, .8)
  padding 2rem
  margin 0 10%
  flex 0 0 auto
  .react-mount
    width 100%
    input[type="checkbox"]
      display none
  .select-wrapper
    .checkbox-wrapper
      max-height 0
      background-color white
      overflow hidden
      transition all .2s ease-in-out
    &.open
      .checkbox-wrapper
        max-height 300px
        overflow auto
        padding 1em
      .select-value:after
        transform translateY(-50%) rotate(180deg)
  .item-label
    color greyBlack
    font-size 1rem
    display block
    padding 1em
    transition background .1s linear
    cursor pointer
    &:hover
    &:active
    &:focus
      background-color accent
  .select-value
    border 1px solid ltestgrey
    display block
    padding 14px 40px 12px 16px
    border-radius 5px
    background-color white
    position relative
    cursor pointer
    &:after
      content "\f063"
      font-family 'FontAwesome', icon
      position absolute
      right 1em
      top 50%
      transform translateY(-50%)
      transition transform .5s ease-in-out
      transform-origin 50% 50%
    .placeholder
      font-size 1.5rem
      font-weight bold
    label
      padding .5em 1em
      background-color lighten(accent, 10)
      color greyBlack
      font-size 1.5rem
      border-radius 5px
      display inline-block
      margin .25em .25em
      &:first-child
        margin-left 0
      &:after
        content 'X'
        font-size .8em
        margin-left 1em
label
  display block
  color greyBlack
  font-size 1.3rem
  margin 1em 0
select
  appearance none
  border 1px solid ltestgrey
  background white
  display inline-block
  padding 14px 40px 12px 16px
  border-radius 5px
  width 100%
  font-size 1.5rem
  font-weight bold
  cursor pointer
  option
    font-size 1rem
.form-group
  width 100%
  display flex
  .input-group
    flex 1 1 50%
    margin 0 1em
    position relative
    &:after
      content "\f063"
      font-family 'FontAwesome', icon
      position absolute
      right 1em
      padding-top 4rem
      top 50%
      transform translateY(-50%)
  [type="submit"]
    appearance none
    background-color darken(accent, 20)
    border-radius 5px
    color white
    border none
    padding 1rem
    font-size 1.4rem
    font-weight bold
    margin 1em auto
    transition background-color .1s ease
    animation roll-gradient .2s linear infinite alternate
    cursor pointer
    &:hover
    &:active
    &:focus
      outline none
      background-color darken(accent, 40)
!

JS 

              
                const { Component } = React;
const { render, findDOMNode } = ReactDOM;

class MultiSelect extends Component {
  constructor(props) {
    super(props);
   this.state = {
     selected: [],
     open: false
   };
  }
  handleChange(e) {
    const select = findDOMNode(this.refs.selectWrapper);
    const selected = select.querySelectorAll('input:checked');
    const realSelect = select.parentNode.parentNode.querySelectorAll('[selected]');
    const values = Array.prototype.map.call(selected, el => {
      return {
        name: el.value,
        id: el.id
      }
    });
    realSelect[0].value = values.map( value => {
      return value.id
    }).join(',');
    this.setState({
      selected: values,
      open: false
    });
  }
  buildGroup(group) {
    return group.options.map( item => {
      return (
        <li>
          <input
            onChange={::this.handleChange}
            type="checkbox" 
            id={item.id} 
            value={item.name}/>
          <label 
            htmlFor={item.id} 
            className="item-label">
            { item.name }
          </label>
        </li>
      )
    });
  }
  toggleMenu() {
    this.setState({
      open: !this.state.open
    });
  }
  render() {
    const {options} = this.props;
    const {selected, open} = this.state;
    return (
      <div ref="selectWrapper" className={classNames('select-wrapper',{
          open: open
        })}>
        {selected && 
          <div className="select-value" onClick={::this.toggleMenu}>
            {(selected.length < 1) &&
              <span className="placeholder">
                All
              </span>
            }
            {selected.map( el => {
            return (
              <span key={el.id}>
              <label 
                htmlFor={el.id}>
                { el.name }
              </label>
             </span>
             )})}
           </div>
         }
        {options && 
         <div className="checkbox-wrapper" onClick={::this.toggleMenu}>
         {options.map( group => {
            return (
              <ul>
                <label>{group.group}</label>
                {this.buildGroup(group)}
              </ul>
             )
          })}
        </div>
        }
      </div>
    );    
  }
};

const selectForms = document.querySelectorAll('[multiselect]');
[].slice.call(selectForms).forEach( select => {
  const mount = document.createElement('div');
  mount.className = 'react-mount';
  select.appendChild(mount);
  let selectOptions = select.querySelectorAll('optgroup');
  const options = Array.prototype.map.call(selectOptions, o => {
    const items = o.querySelectorAll('option');
    const formattedItems = Array.prototype.map.call( items, item => {
      return {
        name: item.innerText,
        id: item.value 
      }
    })
    return {
      group: o.label,
      options: formattedItems
    };
  });
  render(<MultiSelect options={options}/>, mount);
});
!
999px

Console