[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 ``` 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 ``` 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 ``` Google APIs: ```html ``` Microsoft Ajax Content Delivery Network: ```html ``` ### 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 ``` ### 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 ``` **_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 ``` ## 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 ``` Here's what it looks like alongside H5BP's default X-UA-Compatible values: ```html ``` 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 ``` ### 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 ``` ### 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 ``` ### 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 ``` ### 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 ``` ### 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 ``` ### (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 ``` ### 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 ``` ## 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 ``` ### 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 ``` ## 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 ``` ### 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 ``` ## 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 ``` ### 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 ``` ### Pingbacks Your server may be notified when another site links to yours. The href attribute should contain the location of your pingback service. ```html ``` * 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 ``` ### 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 ``` ## 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.*