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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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Insecure Resource

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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.

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JavaScript

About JavaScript Preprocessors

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

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Babel includes JSX processing.

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HTML 

              
                <!doctype html>
<html lang="en">
  <head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.3/css/bootstrap.min.css" integrity="sha384-Zug+QiDoJOrZ5t4lssLdxGhVrurbmBWopoEl+M6BdEfwnCJZtKxi1KgxUyJq13dy" crossorigin="anonymous">

    <title>Example app</title>
  </head>
  <body>
    <div id="app" class="container">
      <h1>Items</h1>
      <div class="list-group">
        <button
          type="button"
          class="list-group-item list-group-item-action"
          v-for="item in items"
        >
          {{ item.title }}
        </button>
      </div>
    
    
    </div>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.3/js/bootstrap.min.js" integrity="sha384-a5N7Y/aK3qNeh15eJKGWxsqtnX/wWdSZSKp+81YjTmS15nvnvxKHuzaWwXHDli+4" crossorigin="anonymous"></script>
    
    <script src="https://cdn.jsdelivr.net/npm/vue"></script>
  </body>
</html>
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CSS
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JS 

              
                var app = new Vue({
  el: '#app',
  data: {
    items: [
      {title: "Morbi", body: "Morbi nec dictum justo. Proin vel ligula pharetra eros vulputate placerat nec sed nisi. Donec consequat quam non tellus porta dapibus. Suspendisse dignissim pharetra tortor, ac pellentesque massa. Nam vitae velit lobortis, pretium odio vitae, condimentum nisi. Morbi ex massa, facilisis euismod quam vitae, sodales varius ipsum. Praesent porttitor erat ut eros euismod, et molestie ipsum maximus. Sed vitae dictum tortor. Sed finibus auctor lacinia."},
      {title: "Fusce", body: "Fusce molestie velit eu tincidunt efficitur. Etiam ultrices dui eu fringilla dictum. Suspendisse fermentum pellentesque orci vitae hendrerit. Curabitur a hendrerit enim. Phasellus vulputate ultrices risus, eu fringilla eros varius in. Nullam dignissim vitae sem in malesuada. Fusce blandit risus vitae tellus suscipit convallis. Proin vitae lobortis magna, id sodales nulla. In viverra sapien lectus, ac lobortis arcu dictum ac. Aenean semper nisi tellus, a sodales enim tempor eget."},
      {title: "Aenean", body: "Aenean et lectus sit amet libero blandit eleifend. Duis quis velit quis felis congue vulputate. Quisque et enim sed elit lobortis tempus ac nec nunc. Curabitur ex dolor, mattis at purus in, placerat accumsan eros. Nulla facilisi. Nullam massa erat, egestas eget vestibulum sit amet, auctor eget ex. Phasellus pharetra sodales eros, ut mattis ex dapibus id. Integer bibendum felis non commodo egestas. Curabitur interdum, elit id pharetra pharetra, tellus augue cursus tortor, non tincidunt lorem urna aliquet justo. Integer bibendum eu mauris ut sagittis. Fusce rhoncus justo in sapien porta, vitae consectetur nunc pulvinar. Pellentesque venenatis et dolor ac tincidunt. Sed nunc velit, commodo id dictum scelerisque, hendrerit at massa."},
      {title: "Rhoncus", body: "Rhoncus eleifend scelerisque. Cras consequat est eu libero faucibus, sed convallis odio posuere. Ut lacinia enim diam. Ut ullamcorper nunc ante, vitae pulvinar diam placerat vel. Orci varius natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Morbi dictum magna sed sem lobortis, in commodo justo pretium. Morbi magna tellus, pellentesque et metus eget, gravida suscipit eros. Donec a dolor non urna laoreet bibendum. In finibus tempor mauris et vulputate. Vestibulum ut urna consequat, tincidunt ante sed, sagittis nibh. Curabitur a luctus nulla. Nam nec bibendum velit. Phasellus eu tellus ut magna malesuada malesuada."},
      {title: "Sed", body: "Sed tellus odio, malesuada eu felis et, vehicula efficitur urna. Ut accumsan, massa in convallis mollis, ligula purus hendrerit lectus, in convallis neque lorem nec ante. Nam mattis, nisl sed dapibus consequat, sapien felis ultricies ante, et pharetra tortor nunc at eros. Sed sagittis est vel est cursus scelerisque. Pellentesque eleifend pellentesque eros. Nulla viverra semper nunc sit amet posuere. Donec pellentesque feugiat libero vitae dapibus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Nam mattis, sapien vitae porta ornare, odio ante aliquet ligula, luctus elementum ipsum lorem porttitor eros. Nulla non dictum lorem, in rutrum velit. Phasellus et tellus at diam efficitur congue. Donec at ex ligula."},
    ]
  }
})
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999px

Console