Goran Spasojevic


HTML5 Boilerplate homepage | Documentation table of contents


Conditional html classes

A series of IE conditional comments apply the relevant IE-specific classes to the html tag. This provides one method of specifying CSS fixes for specific legacy versions of IE. While you may or may not choose to use this technique in your project code, HTML5 Boilerplate’s default CSS does not rely on it.

When using the conditional classes technique, applying classes to the html element has several benefits:

The no-js class

Allows you to more easily explicitly add custom styles when JavaScript is disabled (no-js) or enabled (js). More here: Avoiding the FOUC.

The order of meta tags, and <title>

As recommended by the HTML5 spec ( Specifying the document’s character encoding), add your charset declaration early (before any ASCII art ;) to avoid a potential encoding-related security issue in IE. It should come in the first 1024 bytes.

The charset should also come before the <title> tag, due to potential XSS vectors.

The meta tag for compatibility mode needs to be before all elements except title and meta. And that same meta tag can only be invoked for Google Chrome Frame if it is within the first 1024 bytes.


This makes sure the latest version of IE is used in versions of IE that contain multiple rendering engines. Even if a site visitor is using IE8 or IE9, it’s possible that they’re not using the latest rendering engine their browser contains. To fix this, use:

<meta http-equiv="X-UA-Compatible" content="IE=edge">

The meta tag tells the IE rendering engine it should use the latest, or edge, version of the IE rendering environment.

This meta tag ensures that anyone browsing your site in IE is treated to the best possible user experience that their browser can offer.

This line breaks validation. To avoid this edge case issue it is recommended that you remove this line and use the .htaccess (or other server config) to send these headers instead. You also might want to read Validating: X-UA-Compatible.

If you are serving your site on a non-standard port, you will need to set this header on the server-side. This is because the IE preference option ‘Display intranet sites in Compatibility View’ is checked by default.

Mobile viewport

There are a few different options that you can use with the viewport meta tag. You can find out more in the Apple developer 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">

Favicons and Touch Icon

The shortcut icons should be put in the root directory of your site. 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.


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.

In general, in order to keep page load times to a minimum, it’s best to call any JavaScript at the end of the page because if a script is slow to load from an external server it may cause the whole page to hang. That said, the Modernizr script needs to run before the browser begins rendering the page, so that browsers lacking support for some of the new HTML5 elements are able to handle them properly. Therefore the Modernizr script is the only JavaScript file synchronously loaded at the top of the document.

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.

Google Chrome Frame

The main content area of the boilerplate includes a prompt to install Chrome Frame (which no longer requires administrative rights) for users of IE 6. If you intended to support IE 6, then you should remove the snippet of code.

Google CDN for jQuery

The Google CDN version of the jQuery JavaScript library is referenced towards the bottom of the page using a protocol-independent path (read more about this in the FAQ). A local fallback of jQuery is included for rare instances when the CDN version might not be available, and to facilitate offline development.

Regardless of which JavaScript library you choose to use, it is well worth the time and effort to look up and reference the Google CDN (Content Delivery Network) version. Your users may already have this version cached in their browsers, and Google’s CDN is likely to deliver the asset faster than your server.

Google Analytics Tracking Code

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