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 URL's 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 it's URL and the proper URL extention.

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 Skypack, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ES6 import 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

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.

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 

              
                <div id="app">
  <vue-read-progress color="#33CC00"></vue-read-progress>
  <p v-for="n in 5">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Proin quis sem quis quam imperdiet imperdiet ac id lectus. Aenean tristique quis ipsum vel pretium. Fusce efficitur sem massa, sit amet eleifend mauris lobortis pharetra. Suspendisse dignissim tortor at venenatis faucibus. Donec efficitur vitae metus vel rhoncus. Integer ac odio non urna tincidunt molestie non ut ligula. Etiam auctor porttitor tempor. Ut facilisis sapien nec consectetur blandit. In eu vehicula dolor. Duis ornare ultricies varius. Mauris malesuada consequat felis eget tincidunt. Morbi at tellus leo. Maecenas urna sem, scelerisque in tincidunt sit amet, porttitor quis lectus. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Maecenas massa sem, tincidunt non condimentum id, dictum sed nisi. Mauris tempor tortor at ligula lacinia, non mollis quam sodales. Integer fringilla in purus at sagittis. Cras convallis nisl vitae condimentum volutpat. Duis congue, tortor in tincidunt laoreet, felis eros pellentesque velit, nec porttitor eros magna sed orci. Morbi vitae aliquet arcu. Donec sollicitudin dui ligula, eu tincidunt eros auctor vitae. Interdum et malesuada fames ac ante ipsum primis in faucibus. Donec mattis ornare arcu, at interdum sapien sodales egestas. Vivamus vel feugiat leo, non consequat leo. Quisque mattis non nunc et rutrum. Sed ac nisi ac diam gravida rutrum. Integer finibus blandit dui, id volutpat urna vehicula id. Donec tempus nunc sed ante venenatis, in hendrerit odio euismod. Pellentesque tristique condimentum felis, vitae iaculis felis porta eget. Morbi varius elementum nunc, nec laoreet arcu viverra vitae. Fusce vehicula neque sed dui lobortis, eu tincidunt magna semper. Nam sodales sagittis ipsum, ut congue augue facilisis ac. Nunc porttitor, lectus egestas sagittis tempor, purus orci vestibulum erat, at molestie mi augue ac mauris. Etiam et ipsum elit. Nullam augue nulla, accumsan sit amet ullamcorper a, congue in nibh. Aenean a ex et arcu tristique posuere eu in justo. Integer suscipit tincidunt augue at rhoncus. Proin venenatis aliquet sagittis. Nulla a purus laoreet, porttitor eros quis, tincidunt dui. Maecenas nibh mi, interdum sit amet elit at, malesuada tincidunt nulla. Curabitur ut malesuada erat, nec malesuada leo. Integer porttitor dictum tortor, et laoreet purus egestas in. Duis et ullamcorper orci. Donec ultricies nisi id semper porta. Praesent fringilla velit nec nulla vestibulum facilisis. Nulla tincidunt ut tortor sed euismod. Nunc a enim metus. Vestibulum ultricies, augue sit amet egestas tincidunt, purus nibh laoreet sapien, vehicula maximus tellus leo in nulla. Ut auctor id neque non malesuada. Nulla volutpat ligula eu elementum rutrum. Vestibulum at venenatis sapien. Vivamus at ex tortor. Phasellus eleifend tellus eu ante iaculis, ut ultrices justo scelerisque. Suspendisse potenti. Sed consectetur malesuada euismod. Nam sit amet nibh id turpis iaculis elementum vel vitae enim. Suspendisse finibus ornare velit elementum egestas. Fusce felis augue, aliquam et turpis vel, posuere vulputate ligula.
  </p>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.6.10/vue.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vue-read-progress@1.0.4/dist/vue-read-progress.umd.js"></script>
!

CSS
!

JS 

              
                const VueReadProgress = window['VueReadProgress'];

new Vue({
  el: '#app',
  components: {
    'vue-read-progress': VueReadProgress
  }
});
!
999px

Console