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 

              
                h1 CSS triangle generator
.main
  .ctrl
    ul#values
      li
        label
          span size
          input(name='size', type='range', min='0', max='400', step='any', value='200')
      li
        label
          span height
          input(name='height', type='range', min='0', max='100', step='any', value='50')
          button(data-preset='height:50') 1:2
          button(data-preset='height:100') 1:1
          button(data-preset='height:86.6', onclick='iso.click()') √3:2 (equilateral)
      li
        label
          span angle
          input(name='angle', type='range', min='-100', max='100', step='any', value='0')
          button#iso(data-preset='angle:0') isosceles
    ul#direction
      li
        label
          input(type='radio', name='dir', value='top', checked='')
          span ↑
      li
        label
          input(type='radio', name='dir', value='right')
          span →
      li
        label
          input(type='radio', name='dir', value='bottom')
          span ↓
      li
        label
          input(type='radio', name='dir', value='left')
          span ←
  .out
    pre.
    div.tri
      input#show(type='checkbox', name='')
      label(for='show')  show all borders
      #triangle
!

CSS 

              
                *
*:before
*:after
  box-sizing border-box
html
  font-size 16px

h1
  text-align center
  font-weight normal
  font-size 1.5em
  margin 0.5em


ul,li
  display block
  list-style none
  padding 0
  margin 0


#show:checked~#triangle
  transition 0.3s
  border-color hsl(160, 0%, 20%) hsl(150, 0%, 10%) !important
  filter none
  &:hover
    padding 10px
    background hsl(160, 0%, 40%)
    

.tri
  margin 20px

#triangle
  //transition border .3s
  width 0
  margin-top 20px
  filter drop-shadow(0 0 5px rgba(#f,.5))


#values
  padding 0
  display block
  list-style none
  
  >li
    background rgba(#000, 0.1)
    padding 1px
    margin 10px 0
  
  label
    margin 10px 0
    display block
  
  span
    display inline-block
    width 50px
    text-align right
    vertical-align middle
  
  input
    vertical-align middle
    width 300px
  


#direction
  background rgba(#000, .1)
  padding 10px
  font-size 1.5em
  
  >li
    text-align center
    display inline-grid
    
    input
      width: 1.5em;
      display: block;
      height: 1.5em;
      appearance: block;
      position absolute
      appearance: inherit;
    
      &:checked+span
        background #363
        color white
        text-shadow 0 0 5px white
        box-shadow 0px 0px 0px 1px rgba(#fff, 0.5)
    
    span
      display block
      background #444
      vertical-align middle
      line-height 1.3
      padding 0px 0px
      width 1.5em
      height 1.5em
      transition .3s background-color
      box-shadow 0px 0px 0px 1px rgba(#fff, 0.3)
      
      &:hover
        background-color #336

html
  background #258
  color #ace
  min-height 100%
  margin 10px

pre
  background-color rgba(0, 0, 0, 0.5)
  margin 20px -10px
  color #fff
  padding 10px
  
  .prop
    color #ff3
  
  .value
    color #5ff
  
  .size
    color #f55

button
  background #444
  border none
  color #ddd
  margin-left 10px
  //border-radius 0.2em
  vertical-align middle
  padding .1em .2em !important
  box-shadow 0px 0px 0px 1px rgba(#fff, 0.3)
  transition .3s background-color
  
  &:hover
    background #336
    box-shadow 0px 0px 0px 1px rgba(#fff, 0.5)
  
  &:before
    content '◎ '
    // content '◇ '
    font-size 1em
    line-height 1
    vertical-align middle
    color #fff
    display inline-block
    margin-right 5px
    // padding-right 5px
    // border-right 1px solid #999
  
  &:disabled
    //box-shadow none
    background-color #363
    pointer-events none
    
    &:before
      content '◉ '
      // content '◈ '

.main
  border-top 1px solid transparent
  
@media (min-width 1111px)
  pre
    margin 10px 0
  .main
    display flex
  .ctrl
    flex-grow 1
  .out
    margin-left 10px
    width 600px
    
.main
  border-top 1px solid transparent
@media (max-width 1110px) and (max-height 600px)
  .out
    display flex
    flex-wrap wrap
    align-items flex-start
    >*
      flex 1 1 0
!

JS 

              
                const rng = document.queryAll('#values input[type=range]')
const pst = document.queryAll('[data-preset]')
const tri = document.query('#triangle')
const pre = document.query('pre')
const val = {}
const bdr = ['top', 'right', 'bottom', 'left']
let dir  = document.queryAll('#direction input')

rng.forEach((elm) => {
  val[elm.name] = +elm.value
})

draw()

pst.forEach((btn) => {
  const data = btn.dataset.preset.split(':')
  const input = rng.find((a) => a.name === data[0])
  const val = data[1]
  
  const event = document.createEvent('Event');
  event.initEvent('input', true, false);
  
  function checkButton(){
    btn.disabled = (input.value === val)
  }
  input.addEventListener('input', checkButton)
  btn.addEventListener('click', () => {
    input.value = val
    input.dispatchEvent(event);
    checkButton()
  })
  checkButton()
})

rng.forEach((elm) => {
  elm.addEventListener('input', () => {
    val[elm.name] = +elm.value
    draw()
  })
})

dir.forEach((elm) => {
  elm.addEventListener('change', () => {
    dir = elm.value
    while (bdr[0] !== dir)
      bdr.push(bdr.shift())
    draw()
  })
})

dir = dir.find((elm) => elm.checked).value

draw()

function draw() {
  let style = ''
  const css = {
    width: '0',
    height: '0',
    border: '0 solid transparent'
  }
  css['border-' + bdr[1] + '-width'] = Math.round(val.size * (-val.angle/100 + 1) / 2) + 'px'
  css['border-' + bdr[3] + '-width'] = Math.round(val.size * (val.angle/100 + 1) / 2) + 'px'
  css['border-' + bdr[2]] = Math.round(val.size * val.height/100) + 'px solid black'

  Object.assign(tri.style, css)

  Object.entries(css).forEach(([k, v]) => {
    v = v.replace(/(\d+(px)?)/g, '<span class="size">$1</span>')
    style += '<span class="prop">' + k + '</span>: <span class="value">' + v + '</span>;\n'
  })

  pre.innerHTML = style

}
!
999px

Console