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HTML

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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.

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About the <head>

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CSS

About CSS Preprocessors

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

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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).

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JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient. For instance, CoffeeScript can help prevent easy-to-make mistakes and offer a cleaner syntax and Babel can bring ECMAScript 6 features to browsers that only support ECMAScript 5.

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

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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.

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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.

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HTML 

            
              <button>Hover for a new image</button>
!

CSS 

            
              html, body {
  min-height: 400px;
}

button {
  background: #ddd;
  border: none;
  font-size: 20px;
  padding: 10px 20px;
}

.tippy-tooltip.ajax-theme {
  position: absolute;
  width: 200px;
  padding: 0;
  overflow: hidden;
}

.tippy-tooltip.ajax-theme img {
  display: block;
  max-width: 100%;
}

/* 
We need to "pin" the tooltip absolutely to the bottom or top of the popper element depending on the placement.
*/
.tippy-tooltip.ajax-theme[x-placement^='top'] {
  top: auto !important;
  bottom: 0;
}

.tippy-tooltip.ajax-theme[x-placement^='bottom'] {
  bottom: auto !important;
  top: 0;
}
!

JS 

            
              const INITIAL_CONTENT = '<div style="margin:5px 0;">Loading...</div>'

function applyStyles(popper, tooltip) {
  // Because the tooltip has `position: absolute`,
  // it no longer affects the parent popper's layout.
  // We need to explicitly give it a width.
  popper.style.width = '200px'

  // Setup transition styles on the tooltip itself
  tooltip.style.transitionDuration = '0.2s'
  tooltip.style.transitionProperty = 'visibility, opacity, height'
}

function animateHeight(instance, instanceContent) {
  const { popper } = instance
  const { tooltip, content } = instance.popperChildren
  
  function onTransitionEnd(event) {
    if (event.target === event.currentTarget) {
      content.style.opacity = '1'
      instance.setContent(instanceContent)
    }
  }
  
  // Wait until the height transition has finished before
  // fading the content in. Since we have `overflow: hidden`
  // on the tooltip this isn't actually needed, but if you
  // have an arrow element it will be.
  if (!instance._transitionEndListener) {
    instance._transitionEndListener = onTransitionEnd
  }

  tooltip.addEventListener('transitionend', onTransitionEnd)
  
  // Store the base height of the tooltip when it has the
  // initial Loading... content.
  if (!instance._baseHeight) {
    instance._baseHeight = tooltip.clientHeight
  }

  // Here is where we find out the height of the tooltip
  // when it has the content. We could technically hardcode
  // 200px as the value, but it's useful to know how to do
  // this with dynamic content.
  content.style.opacity = '0'
  
  // Temporarily set the image as the tooltip's content
  // so we can find out the final height of the tooltip.
  instance.setContent(instanceContent)
  const height = tooltip.clientHeight
  
  // Apply the height to the parent popper element.
  popper.style.height = height + 'px'
  
  // Reset the tooltip's height to the base height.
  tooltip.style.height = instance._baseHeight + 'px'
  
  // Cause reflow so we can start the height transition.
  void tooltip.offsetHeight
  
  // Start the transition.
  tooltip.style.height = height + 'px'
  
  // Remove the Loading... content and wait until the
  // transition finishes.
  instance.setContent('')
}

tippy('button', {
  content: INITIAL_CONTENT,
  animation: 'fade',
  animateFill: false,
  theme: 'ajax',
  async onShow(instance) {
    if (instance.state.isFetching === true || instance.state.canFetch === false) {
      return
    }

    instance.state.isFetching = true
    instance.state.canFetch = false
    
    applyStyles(instance.popper, instance.popperChildren.tooltip)
    
    try {
      const response = await fetch('https://unsplash.it/200/?random')
      const blob = await response.blob()
      const url = URL.createObjectURL(blob)
      
      // If the tooltip hid before finishing the request, stop further action
      if (!instance.state.isVisible) {
        return
      }
      
      const img = new Image()
      img.width = 200
      img.height = 200
      img.src = url
      
      animateHeight(instance, img)
    } catch (error) {
      instance.setContent('An error occurred')
    } finally {
      instance.state.isFetching = false
    }
  },
  onHidden(instance) {
    const { tooltip } = instance.popperChildren
    instance.state.canFetch = true
    instance.setContent(INITIAL_CONTENT)
    tooltip.style.height = null
    tooltip.removeEventListener('transitionend', instance._transitionEndListener)
    instance._transitionEndListener = null
  }
})
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999px

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