<pclass="lead">Bootstrap (currently v3.3.5) has a few easy ways to quickly get started, each one appealing to a different skill level and use case. Read through to see what suits your particular needs.</p>
<p><ahref="https://github.com/twbs/bootstrap-sass">Bootstrap ported from Less to Sass</a> for easy inclusion in Rails, Compass, or Sass-only projects.</p>
<p>The folks over at <ahref="https://www.maxcdn.com/">MaxCDN</a> graciously provide CDN support for Bootstrap's CSS and JavaScript. Just use these <ahref="https://www.bootstrapcdn.com/">Bootstrap CDN</a> links.</p>
<p><code>require('bootstrap')</code> will load all of Bootstrap's jQuery plugins onto the jQuery object. The <code>bootstrap</code> module itself does not export anything. You can manually load Bootstrap's jQuery plugins individually by loading the <code>/js/*.js</code> files under the package's top-level directory.</p>
<p>Bootstrap's <code>package.json</code> contains some additional metadata under the following keys:</p>
<ul>
<li><code>less</code> - path to Bootstrap's main <ahref="http://lesscss.org">Less</a> source file</li>
<li><code>style</code> - path to Bootstrap's non-minified CSS that's been precompiled using the default settings (no customization)</li>
<p>Bootstrap uses <ahref="https://github.com/postcss/autoprefixer">Autoprefixer</a> to deal with <ahref="http://webdesign.about.com/od/css/a/css-vendor-prefixes.htm">CSS vendor prefixes</a>. If you're compiling Bootstrap from its Less/Sass source and not using our Gruntfile, you'll need to integrate Autoprefixer into your build process yourself. If you're using precompiled Bootstrap or using our Gruntfile, you don't need to worry about this because Autoprefixer is already integrated into our Gruntfile.</p>
<pclass="lead">Bootstrap is downloadable in two forms, within which you'll find the following directories and files, logically grouping common resources and providing both compiled and minified variations.</p>
<p>Please note that <strong>all JavaScript plugins require jQuery</strong> to be included, as shown in the <ahref="#template">starter template</a>. <ahref="https://github.com/twbs/bootstrap/blob/v3.3.5/bower.json">Consult our <code>bower.json</code></a> to see which versions of jQuery are supported.</p>
<p>This is the most basic form of Bootstrap: precompiled files for quick drop-in usage in nearly any web project. We provide compiled CSS and JS (<code>bootstrap.*</code>), as well as compiled and minified CSS and JS (<code>bootstrap.min.*</code>). CSS <ahref="https://developer.chrome.com/devtools/docs/css-preprocessors">source maps</a> (<code>bootstrap.*.map</code>) are available for use with certain browsers' developer tools. Fonts from Glyphicons are included, as is the optional Bootstrap theme.</p>
<p>The Bootstrap source code download includes the precompiled CSS, JavaScript, and font assets, along with source Less, JavaScript, and documentation. More specifically, it includes the following and more:</p>
<p>The <code>less/</code>, <code>js/</code>, and <code>fonts/</code> are the source code for our CSS, JS, and icon fonts (respectively). The <code>dist/</code> folder includes everything listed in the precompiled download section above. The <code>docs/</code> folder includes the source code for our documentation, and <code>examples/</code> of Bootstrap usage. Beyond that, any other included file provides support for packages, license information, and development.</p>
<h1id="grunt"class="page-header">Compiling CSS and JavaScript</h1>
<pclass="lead">Bootstrap uses <ahref="http://gruntjs.com">Grunt</a> for its build system, with convenient methods for working with the framework. It's how we compile our code, run tests, and more.</p>
<p>To install Grunt, you must <strong>first <ahref="https://nodejs.org/download/">download and install node.js</a></strong> (which includes npm). npm stands for <ahref="https://www.npmjs.com/">node packaged modules</a> and is a way to manage development dependencies through node.js.</p>
<li>Install <code>grunt-cli</code> globally with <code>npm install -g grunt-cli</code>.</li>
<li>Navigate to the root <code>/bootstrap/</code> directory, then run <code>npm install</code>. npm will look at the <ahref="https://github.com/twbs/bootstrap/blob/master/package.json"><code>package.json</code></a> file and automatically install the necessary local dependencies listed there.</li>
</ol>
<p>When completed, you'll be able to run the various Grunt commands provided from the command line.</p>
<h3><code>grunt dist</code> (Just compile CSS and JavaScript)</h3>
<p>Regenerates the <code>/dist/</code> directory with compiled and minified CSS and JavaScript files. As a Bootstrap user, this is normally the command you want.</p>
<h3><code>grunt watch</code> (Watch)</h3>
<p>Watches the Less source files and automatically recompiles them to CSS whenever you save a change.</p>
<h3><code>grunt test</code> (Run tests)</h3>
<p>Runs <ahref="http://jshint.com">JSHint</a> and runs the <ahref="http://qunitjs.com">QUnit</a> tests headlessly in <ahref="http://phantomjs.org">PhantomJS</a>.</p>
<p>Compiles and minifies CSS and JavaScript, builds the documentation website, runs the HTML5 validator against the docs, regenerates the Customizer assets, and more. Requires <ahref="http://jekyllrb.com/docs/installation/">Jekyll</a>. Usually only necessary if you're hacking on Bootstrap itself.</p>
<p>Should you encounter problems with installing dependencies or running Grunt commands, first delete the <code>/node_modules/</code> directory generated by npm. Then, rerun <code>npm install</code>.</p>
<pclass="lead">Start with this basic HTML template, or modify <ahref="#examples">these examples</a>. We hope you'll customize our templates and examples, adapting them to suit your needs.</p>
<p>Copy the HTML below to begin working with a minimal Bootstrap document.</p>
<pclass="lead">Build on the basic template above with Bootstrap's many components. We encourage you to customize and adapt Bootstrap to suit your individual project's needs.</p>
<p>Get the source code for every example below by <ahref="https://github.com/twbs/bootstrap/archive/v3.3.5.zip">downloading the Bootstrap repository</a>. Examples can be found in the <code>docs/examples/</code> directory.</p>
<p><strong><ahref="https://github.com/twbs/bootlint">Bootlint</a></strong> is the official Bootstrap HTML <ahref="http://en.wikipedia.org/wiki/Lint_(software)">linter</a> tool. It automatically checks for several common HTML mistakes in webpages that are using Bootstrap in a fairly "vanilla" way. Vanilla Bootstrap's components/widgets require their parts of the DOM to conform to certain structures. Bootlint checks that instances of Bootstrap components have correctly-structured HTML. Consider adding Bootlint to your Bootstrap web development toolchain so that none of the common mistakes slow down your project's development.</p>
<li>Chat with fellow Bootstrappers using IRC in the <code>irc.freenode.net</code> server, in the <ahref="irc://irc.freenode.net/%23bootstrap">##bootstrap channel</a>.</li>
<li>For help using Bootstrap, ask on <ahref="https://stackoverflow.com/questions/tagged/twitter-bootstrap-3">StackOverflow using the tag <code>twitter-bootstrap-3</code></a>.</li>
<li>Developers should use the keyword <code>bootstrap</code> on packages which modify or add to the functionality of Bootstrap when distributing through <ahref="https://www.npmjs.com/browse/keyword/bootstrap">npm</a> or similar delivery mechanisms for maximum discoverability.</li>
<li>Omit the viewport <code><meta></code> mentioned in <ahref="../css/#overview-mobile">the CSS docs</a></li>
<li>Override the <code>width</code> on the <code>.container</code> for each grid tier with a single width, for example <code>width: 970px !important;</code> Be sure that this comes after the default Bootstrap CSS. You can optionally avoid the <code>!important</code> with media queries or some selector-fu.</li>
<li>If using navbars, remove all navbar collapsing and expanding behavior.</li>
<li>For grid layouts, use <code>.col-xs-*</code> classes in addition to, or in place of, the medium/large ones. Don't worry, the extra-small device grid scales to all resolutions.</li>
</ol>
<p>You'll still need Respond.js for IE8 (since our media queries are still there and need to be processed).
This disables the "mobile site" aspects of Bootstrap.</p>
<h1id="support"class="page-header">Browser and device support</h1>
<pclass="lead">Bootstrap is built to work best in the latest desktop and mobile browsers, meaning older browsers might display differently styled, though fully functional, renderings of certain components.</p>
<p>Specifically, we support the <strong>latest versions</strong> of the following browsers and platforms. On Windows, <strong>we support Internet Explorer 8-11</strong>. More specific support information is provided below.</p>
<p>Unofficially, Bootstrap should look and behave well enough in Chromium and Chrome for Linux, Firefox for Linux, and Internet Explorer 7, though they are not officially supported.</p>
<p>Internet Explorer 8 and 9 are also supported, however, please be aware that some CSS3 properties and HTML5 elements are not fully supported by these browsers. In addition, <strong>Internet Explorer 8 requires the use of <ahref="https://github.com/scottjehl/Respond">Respond.js</a> to enable media query support.</strong></p>
<p>Using Respond.js with CSS hosted on a different (sub)domain (for example, on a CDN) requires some additional setup. <ahref="https://github.com/scottjehl/Respond/blob/master/README.md#cdnx-domain-setup">See the Respond.js docs</a> for details.</p>
<p>Due to browser security rules, Respond.js doesn't work with pages viewed via the <code>file://</code> protocol (like when opening a local HTML file). To test responsive features in IE8, view your pages over HTTP(S). <ahref="https://github.com/scottjehl/Respond/blob/master/README.md#support--caveats">See the Respond.js docs</a> for details.</p>
<p>Respond.js doesn't work with CSS that's referenced via <code>@import</code>. In particular, some Drupal configurations are known to use <code>@import</code>. <ahref="https://github.com/scottjehl/Respond/blob/master/README.md#support--caveats">See the Respond.js docs</a> for details.</p>
<p>IE8 does not fully support <code>box-sizing: border-box;</code> when combined with <code>min-width</code>, <code>max-width</code>, <code>min-height</code>, or <code>max-height</code>. For that reason, as of v3.0.1, we no longer use <code>max-width</code> on <code>.container</code>s.</p>
<p>IE8 has some issues with <code>@font-face</code> when combined with <code>:before</code>. Bootstrap uses that combination with its Glyphicons. If a page is cached, and loaded without the mouse over the window (i.e. hit the refresh button or load something in an iframe) then the page gets rendered before the font loads. Hovering over the page (body) will show some of the icons and hovering over the remaining icons will show those as well. <ahref="https://github.com/twbs/bootstrap/issues/13863">See issue #13863</a> for details.</p>
<p>Bootstrap is not supported in the old Internet Explorer compatibility modes. To be sure you're using the latest rendering mode for IE, consider including the appropriate <code><meta></code> tag in your pages:</p>
<p>This tag is included in all of Bootstrap's documentation and examples to ensure the best rendering possible in each supported version of Internet Explorer.</p>
<p>See <ahref="https://stackoverflow.com/questions/6771258/whats-the-difference-if-meta-http-equiv-x-ua-compatible-content-ie-edge">this StackOverflow question</a> for more information.</p>
<p>Internet Explorer 10 doesn't differentiate <strong>device width</strong> from <strong>viewport width</strong>, and thus doesn't properly apply the media queries in Bootstrap's CSS. Normally you'd just add a quick snippet of CSS to fix this:</p>
<p>However, this doesn't work for devices running Windows Phone 8 versions older than <ahref="http://blogs.windows.com/windows_phone/b/wpdev/archive/2013/10/14/introducing-windows-phone-preview-for-developers.aspx">Update 3 (a.k.a. GDR3)</a>, as it causes such devices to show a mostly desktop view instead of narrow "phone" view. To address this, you'll need to <strong>include the following CSS and JavaScript to work around the bug</strong>.</p>
<p>For more information and usage guidelines, read <ahref="http://timkadlec.com/2013/01/windows-phone-8-and-device-width/">Windows Phone 8 and Device-Width</a>.</p>
<p>The rendering engine of versions of Safari prior to v7.1 for OS X and Safari for iOS v8.0 had some trouble with the number of decimal places used in our <code>.col-*-1</code> grid classes. So if you had 12 individual grid columns, you'd notice that they came up short compared to other rows of columns. Besides upgrading Safari/iOS, you have some options for workarounds:</p>
<p>Support for <code>overflow: hidden</code> on the <code><body></code> element is quite limited in iOS and Android. To that end, when you scroll past the top or bottom of a modal in either of those devices' browsers, the <code><body></code> content will begin to scroll.</p>
<p>Also, note that if you're using a fixed navbar or using inputs within a modal, iOS has a rendering bug that doesn't update the position of fixed elements when the virtual keyboard is triggered. A few workarounds for this include transforming your elements to <code>position: absolute</code> or invoking a timer on focus to try to correct the positioning manually. This is not handled by Bootstrap, so it is up to you to decide which solution is best for your application.</p>
<p>The <code>.dropdown-backdrop</code> element isn't used on iOS in the nav because of the complexity of z-indexing. Thus, to close dropdowns in navbars, you must directly click the dropdown element (or <ahref="https://developer.mozilla.org/en-US/docs/Web/Events/click#Safari_Mobile">any other element which will fire a click event in iOS</a>).</p>
<p>Page zooming inevitably presents rendering artifacts in some components, both in Bootstrap and the rest of the web. Depending on the issue, we may be able to fix it (search first and then open an issue if need be). However, we tend to ignore these as they often have no direct solution other than hacky workarounds.</p>
<h2id="support-sticky-hover-mobile">Sticky <code>:hover</code>/<code>:focus</code> on mobile</h2>
<p>Even though real hovering isn't possible on most touchscreens, most mobile browsers emulate hovering support and make <code>:hover</code> "sticky". In other words, <code>:hover</code> styles start applying after tapping an element and only stop applying after the user taps some other element. This can cause Bootstrap's <code>:hover</code> states to become unwantedly "stuck" on such browsers. Some mobile browsers also make <code>:focus</code> similarly sticky. There is currently no simple workaround for these issues other than removing such styles entirely.</p>
<p>Even in some modern browsers, printing can be quirky.</p>
<p>In particular, as of Chrome v32 and regardless of margin settings, Chrome uses a viewport width significantly narrower than the physical paper size when resolving media queries while printing a webpage. This can result in Bootstrap's extra-small grid being unexpectedly activated when printing. <ahref="https://github.com/twbs/bootstrap/issues/12078">See #12078 for some details.</a> Suggested workarounds:</p>
<p>Also, as of Safari v8.0, fixed-width <code>.container</code>s can cause Safari to use an unusually small font size when printing. See <ahref="https://github.com/twbs/bootstrap/issues/14868">#14868</a> for more details. One potential workaround for this is adding the following CSS:</p>
<p>Out of the box, Android 4.1 (and even some newer releases apparently) ship with the Browser app as the default web browser of choice (as opposed to Chrome). Unfortunately, the Browser app has lots of bugs and inconsistencies with CSS in general.</p>
<p>On <code><select></code> elements, the Android stock browser will not display the side controls if there is a <code>border-radius</code> and/or <code>border</code> applied. (See <ahref="https://stackoverflow.com/questions/14744437/html-select-box-not-showing-drop-down-arrow-on-android-version-4-0-when-set-with">this StackOverflow question</a> for details.) Use the snippet of code below to remove the offending CSS and render the <code><select></code> as an unstyled element on the Android stock browser. The user agent sniffing avoids interference with Chrome, Safari, and Mozilla browsers.</p>
<p>In order to provide the best possible experience to old and buggy browsers, Bootstrap uses <ahref="http://browserhacks.com">CSS browser hacks</a> in several places to target special CSS to certain browser versions in order to work around bugs in the browsers themselves. These hacks understandably cause CSS validators to complain that they are invalid. In a couple places, we also use bleeding-edge CSS features that aren't yet fully standardized, but these are used purely for progressive enhancement.</p>
<p>These validation warnings don't matter in practice since the non-hacky portion of our CSS does fully validate and the hacky portions don't interfere with the proper functioning of the non-hacky portion, hence why we deliberately ignore these particular warnings.</p>
<p>Our HTML docs likewise have some trivial and inconsequential HTML validation warnings due to our inclusion of a workaround for <ahref="https://bugzilla.mozilla.org/show_bug.cgi?id=654072">a certain Firefox bug</a>.</p>
<h1id="third-parties"class="page-header">Third party support</h1>
<pclass="lead">While we don't officially support any third party plugins or add-ons, we do offer some useful advice to help avoid potential issues in your projects.</p>
<p>Some third party software, including Google Maps and Google Custom Search Engine, conflict with Bootstrap due to <code>* { box-sizing: border-box; }</code>, a rule which makes it so <code>padding</code> does not affect the final computed width of an element. Learn more about <ahref="https://css-tricks.com/box-sizing/">box model and sizing at CSS Tricks</a>.</p>
<pclass="lead">Bootstrap follows common web standards and—with minimal extra effort—can be used to create sites that are accessible to those using <abbrtitle="Assistive Technology"class="initialism">AT</abbr>.</p>
<p>If your navigation contains many links and comes before the main content in the DOM, add a <code>Skip to main content</code> link before the navigation (for a simple explanation, see this <ahref="http://a11yproject.com/posts/skip-nav-links/">A11Y Project article on skip navigation links</a>). Using the <code>.sr-only</code> class will visually hide the skip link, and the <code>.sr-only-focusable</code> class will ensure that the link becomes visible once focused (for sighted keyboard users).</p>
<p>Due to long-standing shortcomings/bugs in Chrome (see <ahref="https://code.google.com/p/chromium/issues/detail?id=262171"title="Chromium bug tracker - Issue 262171: Focus should cycle from named anchor">issue 262171 in the Chromium bug tracker</a>) and Internet Explorer (see this article on <ahref="http://accessibleculture.org/articles/2010/05/in-page-links/">in-page links and focus order</a>), you will need to make sure that the target of your skip link is at least programmatically focusable by adding <code>tabindex="-1"</code>.</p>
<p>In addition, you may want to explicitly suppress a visible focus indication on the target (particularly as Chrome currently also sets focus on elements with <code>tabindex="-1"</code> when they are clicked with the mouse) with <code>#content:focus { outline: none; }</code>.</p>
<p>Note that this bug will also affect any other in-page links your site may be using, rendering them useless for keyboard users. You may consider adding a similar stop-gap fix to all other named anchors / fragment identifiers that act as link targets.</p>
<spanclass="nt"><a</span><spanclass="na">href=</span><spanclass="s">"#content"</span><spanclass="na">class=</span><spanclass="s">"sr-only sr-only-focusable"</span><spanclass="nt">></span>Skip to main content<spanclass="nt"></a></span>
<p>When nesting headings (<code><h1></code> - <code><h6></code>), your primary document header should be an <code><h1></code>. Subsequent headings should make logical use of <code><h2></code> - <code><h6></code> such that screen readers can construct a table of contents for your pages.</p>
<p>Learn more at <ahref="http://squizlabs.github.io/HTML_CodeSniffer/Standards/Section508/">HTML CodeSniffer</a> and <ahref="http://accessibility.psu.edu/headings">Penn State's AccessAbility</a>.</p>
<p>Currently, some of the default color combinations available in Bootstrap (such as the various <ahref="../css/#buttons">styled button</a> classes, some of the code highlighting colors used for <ahref="../css/#code-block">basic code blocks</a>, the <code>.bg-primary</code><ahref="../css/#helper-classes-backgrounds">contextual background</a> helper class, and the default link color when used on a white background) have a low contrast ratio (below the <ahref="http://www.w3.org/TR/WCAG20/#visual-audio-contrast-contrast">recommended ratio of 4.5:1</a>). This can cause problems to users with low vision or who are color blind. These default colors may need to be modified to increase their contrast and legibility.</p>
<pclass="lead">Bootstrap is released under the MIT license and is copyright 2015 Twitter. Boiled down to smaller chunks, it can be described with the following conditions.</p>
<li>Include the source of Bootstrap itself, or of any modifications you may have made to it, in any redistribution you may assemble that includes it</li>
<li>Submit changes that you make to Bootstrap back to the Bootstrap project (though such feedback is encouraged)</li>
<p>The full Bootstrap license is located <ahref="https://github.com/twbs/bootstrap/blob/master/LICENSE">in the project repository</a> for more information.</p>
<pclass="lead">Community members have translated Bootstrap's documentation into various languages. None are officially supported and they may not always be up to date.</p>
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<p>Designed and built with all the love in the world by <ahref="https://twitter.com/mdo"target="_blank">@mdo</a> and <ahref="https://twitter.com/fat"target="_blank">@fat</a>.</p>
<p>Maintained by the <ahref="https://github.com/orgs/twbs/people">core team</a> with the help of <ahref="https://github.com/twbs/bootstrap/graphs/contributors">our contributors</a>.</p>
<p>Code licensed under <arel="license"href="https://github.com/twbs/bootstrap/blob/master/LICENSE"target="_blank">MIT</a>, documentation under <arel="license"href="https://creativecommons.org/licenses/by/3.0/"target="_blank">CC BY 3.0</a>.</p>
