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HTML5 Boilerplate homepage | Documentation table of contents


By default, HTML5 Boilerplate provides two html pages:

  • index.html - a default HTML skeleton that should form the basis of all pages on your website
  • 404.html - a placeholder 404 error page


The no-js Class

The no-js class is provided in order to allow you to more easily and explicitly add custom styles based on whether JavaScript is disabled (.no-js) or enabled (.js). Using this technique also helps avoid the FOUC.

Language Attribute

Please consider specifying the language of your content by adding a value to the lang attribute in the <html> as in this example:

<html class="no-js" lang="en">

The order of the <title> and <meta> tags

The charset declaration (<meta charset="utf-8">) must be included completely within the first 1024 bytes of the document and should be specified as early as possible (before any content that could be controlled by an attacker, such as a <title> element) in order to avoid a potential encoding-related security issue in Internet Explorer

Meta Description

The description meta tag provides a short description of the page. In some situations this description is used as a part of the snippet shown in the search results.

<meta name="description" content="This is a description">

Google's Create good meta descriptions documentation has useful tips on creating an effective description.

Mobile Viewport

There are a few different options that you can use with the viewport meta tag. You can find out more in the MDN Web Docs. HTML5 Boilerplate comes with a simple setup that strikes a good balance for general use cases.

<meta name="viewport" content="width=device-width, initial-scale=1">

If you want to take advantage of edge-to-edge displays of iPhone X/XS/XR you can do so with additional viewport parameters. Check the WebKit blog for details.

Web App Manifest

HTML5 Boilerplate includes a simple web app manifest file.

The web app manifest is a simple JSON file that allows you to control how your app appears on a device's home screen, what it looks like when it launches in that context and what happens when it is launched. This allows for much greater control over the UI of a saved site or web app on a mobile device.

It's linked to from the HTML as follows:

<link rel="manifest" href="site.webmanifest">

Our site.webmanifest contains a very skeletal "app" definition, just to show the basic usage. You should fill this file out with more information about your site or application

Favicons and Touch Icon

The shortcut icons should be put in the root directory of your site. favicon.ico is automatically picked up by browsers if it's placed in the root. HTML5 Boilerplate comes with a default set of icons (include favicon and one Apple Touch Icon) that you can use as a baseline to create your own.

Please refer to the more detailed description in the Extend section of these docs.

The Content Area

The central part of the boilerplate template is pretty much empty. This is intentional, in order to make the boilerplate suitable for both web page and web app development.

Browser Upgrade Prompt

The main content area of the boilerplate includes a prompt to install an up to date browser for users of IE 9 and lower. If you intended to support IE, then you should edit or remove the snippet of code.


HTML5 Boilerplate uses a custom build of Modernizr.

Modernizr is a JavaScript library which adds classes to the html element based on the results of feature test and which ensures that all browsers can make use of HTML5 elements (as it includes the HTML5 Shiv). This allows you to target parts of your CSS and JavaScript based on the features supported by a browser.

Starting with version 3 Modernizr can be customized using the modernizr-config.json and the Modernizr command line utility.

What About Polyfills?

If you need to include polyfills in your project, you must make sure those load before any other JavaScript. If you're using a polyfill CDN service, like, just put it before the other scripts in the bottom of the page:

    <script src="js/vendor/modernizr-3.8.0.min.js"></script>
    <script src=""></script>
    <script src="" integrity="sha256-CSXorXvZcTkaix6Yvo6HppcZGetbYMGWSFlBw8HfCJo=" crossorigin="anonymous"></script>
    <script>window.jQuery || document.write('<script src="js/vendor/jquery-3.4.1.min.js"><\/script>')</script>
    <script src="js/plugins.js"></script>
    <script src="js/main.js"></script>

If you like to just include the polyfills yourself, you could include them in js/plugins.js. When you have a bunch of polyfills to load in, you could also create a polyfills.js file in the js/vendor directory or include the files individually and combine them using a build tool. Always ensure that the polyfills are all loaded before any other JavaScript.

There are some misconceptions about Modernizr and polyfills. It's important to understand that Modernizr just handles feature checking, not polyfilling itself. The only thing Modernizr does regarding polyfills is that the team maintains a huge list of cross Browser polyfills.

jQuery CDN for jQuery

The jQuery CDN version of the jQuery JavaScript library is referenced towards the bottom of the page. A local fallback of jQuery is included for rare instances when the CDN version might not be available, and to facilitate offline development.

The jQuery CDN version was chosen over other potential candidates (like Google's Hosted Libraries) because it's fast (comparable or faster than Google by some measures) and, (unlike Google's CDN) is available to China's hundreds of millions of internet users. For many years we chose the Google Hosted version over the jQuery CDN because it was available over HTTPS (the jQuery CDN was not,) and it offered a better chance of hitting the cache lottery owing to the popularity of the Google CDN. The first issue is no longer valid and the second is far outweighed by being able to serve jQuery to users in China.

While the jQuery CDN is a strong default solution your site or application may require a different configuration. Testing your site with services like WebPageTest and browser tools like PageSpeed Insights will help you examine the real world performance of your site and can show where you can optimize your specific site or application.

Google Universal Analytics Tracking Code

Finally, an optimized version of the Google Universal Analytics tracking code is included.

We use analytics.js rather than the newer gtag.js as it's faster and supports tasks and plugins

The beacon transport mechanism is used to send all hits which saves HTTP requests and improves performance.

Google recommends that this script be placed at the top of the page. Factors to consider: if you place this script at the top of the page, you’ll be able to count users who don’t fully load the page, and you’ll incur the max number of simultaneous connections of the browser.

Further information:

N.B. The Google Analytics snippet is included by default mainly because Google Analytics is currently one of the most popular tracking solutions out there. However, its usage isn't set in stone, and you SHOULD consider exploring the alternatives and use whatever suits your needs best.

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