[HTML5 Boilerplate homepage](http://html5boilerplate.com) | [Documentation

table of contents](README.md)

# Extend and customise HTML5 Boilerplate

Here is some useful advice for how you can make your project with HTML5

Boilerplate even better. We don't want to include it all by default, as not

everything fits with everyone's needs.

## DNS prefetching

In short, DNS Prefetching is a method of informing the browser of domain names

referenced on a site so that the client can resolve the DNS for those hosts,

cache them, and when it comes time to use them, have a faster turn around on

the request.

### Implicit prefetches

There is a lot of prefetching done for you automatically by the browser. When

the browser encounters an anchor in your html that does not share the same

domain name as the current location the browser requests, from the client OS,

the IP address for this new domain. The client first checks its cache and

then, lacking a cached copy, makes a request from a DNS server. These requests

happen in the background and are not meant to block the rendering of the

page.

The goal of this is that when the foreign IP address is finally needed it will

already be in the client cache and will not block the loading of the foreign

content. Less requests result in faster page load times. The perception of this

is increased on a mobile platform where DNS latency can be greater.

#### Disable implicit prefetching

```html

<meta http-equiv="x-dns-prefetch-control" content="off">

```

Even with X-DNS-Prefetch-Control meta tag (or http header) browsers will still

prefetch any explicit dns-prefetch links.

**_WARNING:_** THIS MAY MAKE YOUR SITE SLOWER IF YOU RELY ON RESOURCES FROM

FOREIGN DOMAINS.

### Explicit prefetches

Typically the browser only scans the HTML for foreign domains. If you have

resources that are outside of your HTML (a javascript request to a remote

server or a CDN that hosts content that may not be present on every page of

your site, for example) then you can queue up a domain name to be prefetched.

```html

<link rel="dns-prefetch" href="//example.com">

<link rel="dns-prefetch" href="//ajax.googleapis.com">

```

You can use as many of these as you need, but it's best if they are all

immediately after the [Meta

Charset](https://developer.mozilla.org/en/HTML/Element/meta#attr-charset)

element (which should go right at the top of the `head`), so the browser can

act on them ASAP.

#### Common Prefetch Links

Amazon S3:

```html

<link rel="dns-prefetch" href="//s3.amazonaws.com">

```

Google APIs:

```html

<link rel="dns-prefetch" href="//ajax.googleapis.com">

```

Microsoft Ajax Content Delivery Network:

```html

<link rel="dns-prefetch" href="//ajax.microsoft.com">

<link rel="dns-prefetch" href="//ajax.aspnetcdn.com">

```

### Browser support for DNS prefetching

Chrome, Firefox 3.5+, Safari 5+, Opera (Unknown), IE 9 (called "Pre-resolution"

on blogs.msdn.com)

### Further reading about DNS prefetching

* https://developer.mozilla.org/En/Controlling_DNS_prefetching

* http://dev.chromium.org/developers/design-documents/dns-prefetching

* http://www.apple.com/safari/whats-new.html

* http://blogs.msdn.com/b/ie/archive/2011/03/17/internet-explorer-9-network-performance-improvements.aspx

* http://dayofjs.com/videos/22158462/web-browsers_alex-russel

## Search

### Direct search spiders to your sitemap

[Learn how to make a sitemap](http://www.sitemaps.org/protocol.php)

```html

<link rel="sitemap" type="application/xml" title="Sitemap" href="/sitemap.xml">

```

### Hide pages from search engines

According to Heather Champ, former community manager at Flickr, you should not

allow search engines to index your "Contact Us" or "Complaints" page if you

value your sanity. This is an HTML-centric way of achieving that.

```html

<meta name="robots" content="noindex">

```

**_WARNING:_** DO NOT INCLUDE ON PAGES THAT SHOULD APPEAR IN SEARCH ENGINES.

### Firefox and IE Search Plugins

Sites with in-site search functionality should be strongly considered for a

browser search plugin. A "search plugin" is an XML file which defines how your

plugin behaves in the browser. [How to make a browser search

plugin](http://www.google.com/search?ie=UTF-8&q=how+to+make+browser+search+plugin).

```html

<link rel="search" title="" type="application/opensearchdescription+xml" href="">

```

## Internet Explorer

### Prompt users to switch to "Desktop Mode" in IE10 Metro

IE10 does not support plugins, such as Flash, in Metro mode. If your site

requires plugins, you can let users know that via the X-UA-Compatible meta

element, which will prompt them to switch to Desktop Mode.

```html

<meta http-equiv="X-UA-Compatible" content="requiresActiveX=true">

```

Here's what it looks like alongside H5BP's default X-UA-Compatible values:

```html

<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1,requiresActiveX=true">

```

You can find more information in [Microsoft's IEBlog post about prompting for

plugin use in IE10 Metro

Mode](http://blogs.msdn.com/b/ie/archive/2012/01/31/web-sites-and-a-plug-in-free-web.aspx).

### IE Pinned Sites (IE9+)

Enabling your application for pinning will allow IE9 users to add it to their

Windows Taskbar and Start Menu. This comes with a range of new tools that you

can easily configure with the elements below. See more [documentation on IE9

Pinned Sites](http://msdn.microsoft.com/en-us/library/gg131029.aspx).

### Name the Pinned Site for Windows

Without this rule, Windows will use the page title as the name for your

application.

```html

<meta name="application-name" content="Sample Title">

```

### Give your Pinned Site a tooltip

You know — a tooltip. A little textbox that appears when the user holds their

mouse over your Pinned Site's icon.

```html

<meta name="msapplication-tooltip" content="A description of what this site does.">

```

### Set a default page for your Pinned Site

If the site should go to a specific URL when it is pinned (such as the

homepage), enter it here. One idea is to send it to a special URL so you can

track the number of pinned users, like so:

`http://www.example.com/index.html?pinned=true`

```html

<meta name="msapplication-starturl" content="http://www.example.com/index.html?pinned=true">

```

### Recolor IE's controls manually for a Pinned Site

IE9+ will automatically use the overall color of your Pinned Site's favicon to

shade its browser buttons. UNLESS you give it another color here. Only use

named colors (`red`) or hex colors (`#ff0000`).

```html

<meta name="msapplication-navbutton-color" content="#ff0000">

```

### Manually set the window size of a Pinned Site

If the site should open at a certain window size once pinned, you can specify

the dimensions here. It only supports static pixel dimensions. 800x600

minimum.

```html

<meta name="msapplication-window" content="width=800;height=600">

```

### Jump List "Tasks" for Pinned Sites

Add Jump List Tasks that will appear when the Pinned Site's icon gets a

right-click. Each Task goes to the specified URL, and gets its own mini icon

(essentially a favicon, a 16x16 .ICO). You can add as many of these as you

need.

```html

<meta name="msapplication-task" content="name=Task 1;action-uri=http://host/Page1.html;icon-uri=http://host/icon1.ico">

<meta name="msapplication-task" content="name=Task 2;action-uri=http://microsoft.com/Page2.html;icon-uri=http://host/icon2.ico">

```

### (Windows 8) High quality visuals for Pinned Sites

Windows 8 adds the ability for you to provide a PNG tile image and specify the

tile's background color. [Full details on the IE

blog](http://blogs.msdn.com/b/ie/archive/2012/06/08/high-quality-visuals-for-pinned-sites-in-windows-8.aspx).

* Create a 144x144 image of your site icon, filling all of the canvas, and

  using a transparent background.

* Save this image as a 32-bit PNG and optimize it without reducing

  colour-depth. It can be named whatever you want (e.g. `metro-tile.png`).

* To reference the tile and its color, add the HTML `meta` elements described

  in the IE Blog post.

### (Windows 8) Badges for Pinned Sites

IE10 will poll an XML document for badge information to display on your app's

tile in the Start screen. The user will be able to receive these badge updates

even when your app isn't actively running. The badge's value can be a number,

or one of a predefined list of glyphs.

* [Tutorial on IEBlog with link to badge XML schema](http://blogs.msdn.com/b/ie/archive/2012/04/03/pinned-sites-in-windows-8.aspx)

* [Available badge values](http://msdn.microsoft.com/en-us/library/ie/br212849.aspx)

```html

<meta name="msapplication-badge" value="frequency=NUMBER_IN_MINUTES;polling-uri=http://www.example.com/path/to/file.xml">

```

### Suppress IE6 image toolbar

Kill IE6's pop-up-on-mouseover toolbar for images that can interfere with

certain designs and be pretty distracting in general.

```html

<meta http-equiv="imagetoolbar" content="false">

```

## Social Networks

### Facebook Open Graph data

You can control the information that Facebook and others display when users

share your site. Below are just the most basic data points you might need. For

specific content types (including "website"), see [Facebook's built-in Open

Graph content

templates](https://developers.facebook.com/docs/opengraph/objects/builtin/).

Take full advantage of Facebook's support for complex data and activity by

following the [Open Graph

tutorial](https://developers.facebook.com/docs/opengraph/tutorial/).

```html

<meta property="og:title" content="">

<meta property="og:description" content="">

<meta property="og:image" content="">

```

### Twitter Cards

Twitter provides a snippet specification that serves a similar purpose to Open

Graph. In fact, Twitter will use Open Graph when Cards is not available. Note

that, as of this writing, Twitter requires that app developers activate Cards

on a per-domain basis. You can read more about the various snippet formats

and application process in the [official Twitter Cards

documentation](https://dev.twitter.com/docs/cards).

```html

<meta name="twitter:card" content="summary">

<meta name="twitter:site" content="@site_account">

<meta name="twitter:creator" content="@individual_account">

<meta name="twitter:url" content="http://www.example.com/path/to/page.html">

<meta name="twitter:title" content="">

<meta name="twitter:description" content="">

<meta name="twitter:image" content="http://www.example.com/path/to/image.jpg">

```

## URLs

### Canonical URL

Signal to search engines and others "Use this URL for this page!" Useful when

parameters after a `#` or `?` is used to control the display state of a page.

`http://www.example.com/cart.html?shopping-cart-open=true` can be indexed as

the cleaner, more accurate `http://www.example.com/cart.html`.

```html

<link rel="canonical" href="">

```

### Official shortlink

Signal to the world "This is the shortened URL to use this page!" Poorly

supported at this time. Learn more by reading the [article about shortlinks on

the Microformats wiki](http://microformats.org/wiki/rel-shortlink).

```html

<link rel="shortlink" href="h5bp.com">

```

## News Feeds

### RSS

Have an RSS feed? Link to it here. Want to [learn how to write an RSS feed from

scratch](http://www.rssboard.org/rss-specification)?

```html

<link rel="alternate" type="application/rss+xml" title="RSS" href="/rss.xml">

```

### Atom

Atom is similar to RSS, and you might prefer to use it instead of or in

addition to it. [See what Atom's all

about](http://www.atomenabled.org/developers/syndication/).

```html

<link rel="alternate" type="application/atom+xml" title="Atom" href="/atom.xml">

```

### Pingbacks

Your server may be notified when another site links to yours. The href

attribute should contain the location of your pingback service.

```html

<link rel="pingback" href="">

```

* High-level explanation: http://codex.wordpress.org/Introduction_to_Blogging#Pingbacks

* Step-by-step example case: http://www.hixie.ch/specs/pingback/pingback-1.0#TOC5

* PHP pingback service: http://blog.perplexedlabs.com/2009/07/15/xmlrpc-pingbacks-using-php/

## App Stores

### Install a Chrome Web Store app

Users can install a Chrome app directly from your website, as long as the app

and site have been associated via Google's Webmaster Tools. Read more on

[Chrome Web Store's Inline Installation

docs](https://developers.google.com/chrome/web-store/docs/inline_installation).

```html

<link rel="chrome-webstore-item" href="https://chrome.google.com/webstore/detail/APP_ID">

```

### Smart App Banners in iOS 6 Safari

Stop bothering everyone with gross modals advertising your entry in the App Store.

This bit of code will unintrusively allow the user the option to download your iOS

app, or open it with some data about the user's current state on the website.

```html

<meta name="apple-itunes-app" content="app-id=APP_ID,app-argument=SOME_TEXT">

```

## Google Analytics augments

### More tracking settings

The [optimized Google Analytics

snippet](http://mathiasbynens.be/notes/async-analytics-snippet) included with

HTML5 Boilerplate includes something like this:

```js

var _gaq = [['_setAccount', 'UA-XXXXX-X'], ['_trackPageview']];

```

In case you need more settings, just extend the array literal instead of

[`.push()`ing to the

array](http://mathiasbynens.be/notes/async-analytics-snippet#dont-push-it)

afterwards:

```js

var _gaq = [['_setAccount', 'UA-XXXXX-X'], ['_trackPageview'], ['_setAllowAnchor', true]];

```

### Anonymize IP addresses

In some countries, no personal data may be transferred outside jurisdictions

that do not have similarly strict laws (i.e. from Germany to outside the EU).

Thus a webmaster using the Google Analytics script may have to ensure that no

personal (trackable) data is transferred to the US. You can do that with [the

`_gat.anonymizeIp`

option](http://code.google.com/apis/analytics/docs/gaJS/gaJSApi_gat.html#_gat._anonymizeIp).

In use it looks like this:

```js

var _gaq = [['_setAccount', 'UA-XXXXX-X'], ['_gat._anonymizeIp'], ['_trackPageview']];

```

### Track jQuery AJAX requests in Google Analytics

An article by @JangoSteve explains how to [track jQuery AJAX requests in Google

Analytics](http://www.alfajango.com/blog/track-jquery-ajax-requests-in-google-analytics/).

Add this to `plugins.js`:

```js

/*

 * Log all jQuery AJAX requests to Google Analytics

 * See: http://www.alfajango.com/blog/track-jquery-ajax-requests-in-google-analytics/

 */

if (typeof _gaq !== "undefined" && _gaq !== null) {

    $(document).ajaxSend(function(event, xhr, settings){

        _gaq.push(['_trackPageview', settings.url]);

    });

}

```

### Track JavaScript errors in Google Analytics

Add this function after `_gaq` is defined:

```js

(function(window){

    var undefined,

        link = function (href) {

            var a = window.document.createElement('a');

            a.href = href;

            return a;

        };

    window.onerror = function (message, file, row) {

        var host = link(file).hostname;

        _gaq.push([

            '_trackEvent',

            (host == window.location.hostname || host == undefined || host == '' ? '' : 'external ') + 'error',

            message, file + ' LINE: ' + row, undefined, undefined, true

        ]);

    };

}(window));

```

### Track page scroll

Add this function after `_gaq` is defined:

```js

$(function(){

    var isDuplicateScrollEvent,

        scrollTimeStart = new Date,

        $window = $(window),

        $document = $(document),

        scrollPercent;

    $window.scroll(function() {

        scrollPercent = Math.round(100 * ($window.height() + $window.scrollTop())/$document.height());

        if (scrollPercent > 90 && !isDuplicateScrollEvent) { //page scrolled to 90%

            isDuplicateScrollEvent = 1;

            _gaq.push(['_trackEvent', 'scroll',

                'Window: ' + $window.height() + 'px; Document: ' + $document.height() + 'px; Time: ' + Math.round((new Date - scrollTimeStart )/1000,1) + 's',

                undefined, undefined, true

            ]);

        }

    });

});

```

## Miscellaneous

* Use [HTML5

  polyfills](https://github.com/Modernizr/Modernizr/wiki/HTML5-Cross-browser-Polyfills).

* Use [Microformats](http://microformats.org/wiki/Main_Page) (via

  [microdata](http://microformats.org/wiki/microdata)) for optimum search

  results

  [visibility](http://googlewebmastercentral.blogspot.com/2009/05/introducing-rich-snippets.html).

* If you're building a web app you may want [native style momentum scrolling in

  iOS5](http://johanbrook.com/browsers/native-momentum-scrolling-ios-5/) using

  `-webkit-overflow-scrolling: touch`.

* Avoid development/stage websites "leaking" into SERPs (search engine results

  page) by [implementing X-Robots-tag

  headers](https://github.com/h5bp/html5-boilerplate/issues/804).

* Screen readers currently have less-than-stellar support for HTML5 but the JS

  script [accessifyhtml5.js](https://github.com/yatil/accessifyhtml5.js) can

  help increase accessibility by adding ARIA roles to HTML5 elements.

*Many thanks to [Brian Blakely](https://github.com/brianblakely) for

contributing much of this information.*