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HTML

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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.

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Insecure Resource

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CSS

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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

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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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Packages

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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.

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HTML 

              
                <h1>Improving Web Font Performance with Local Storage (Demo)</h1>

<p>I am speaking on literary criticism, and in the world in which we are actually living that is almost as unpromising as speaking about peace. This is not a peaceful age, and it is not a critical age. In the Europe of the last ten years literary criticism of the older kind — criticism that is really judicious, scrupulous, fair-minded, treating a work of art as a thing of value in itself — has been next door to impossible.</p>

<p class="p">Demo by Luis Vieira. <a href="http://www.sitepoint.com/improving-font-performance-subsetting-local-storage/" target="_blank">See article</a> (publishing April 7, 2015).</p>
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CSS 

              
                body {
  text-align: center;
  line-height: 1.5;
  padding: 0 30px;
}

.fallback {
  font-family: 'Georgia', serif;
  line-height: 1.7em;
  letter-spacing: 1px;
  font-size: 15px;
}

.webFont {
  font-family: 'vollkornregular', serif;
  line-height: 1.6em;
  letter-spacing: 1px;
  font-size: 16px;
}

p {
  text-align: left;
}

.p {
  padding-top: 100px;
  text-align: center;
  font-size: 14px;
}
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JS 

              
                (function () {
  'use strict';
  document.documentElement.className = 'fallback';
  var css_href = 'https://codepen.io/SitePoint/pen/6c6dc49b39b410083cd30ac1f16be2fa.css';
  var localStorageSupported = function() {
    try {
      localStorage.setItem('test', 'test');
      localStorage.removeItem('test');
      return true;
    } catch(e) {
      return false;
    }
  }

  if (localStorageSupported() && localStorage.spdemowebFonts) {
    injectRawStyle(localStorage.getItem('spdemowebFonts'));
  } else {
    window.onload = function() {
      injectFontsStylesheet();
    }
  }

  function injectFontsStylesheet() {
    var xhr = new XMLHttpRequest();
      xhr.open('GET', css_href, true);
      xhr.onreadystatechange = function() {
        if (xhr.readyState === 4) {
          injectRawStyle(xhr.responseText);
          localStorage.setItem('spdemowebFonts', xhr.responseText);
        }
      }
    xhr.send();
  }

  function injectRawStyle(text) {
    var style = document.createElement('style');
    style.innerHTML = text;
    document.getElementsByTagName('head')[0].appendChild(style);
    document.documentElement.className = 'webFont';
  }
}());
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999px

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