Bootstrap Install
Irmgard Verzi
require('bootstrap') will load all of Bootstrap's jQuery plugins onto the jQuery object. The bootstrap module itself does not export anything. You can manually load Bootstrap's jQuery plugins individually by loading the /js/*.js files under the package's top-level directory.
Bootstrap uses Autoprefixer to deal with CSS vendor prefixes. 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.
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 (bootstrap.*), as well as compiled and minified CSS and JS (bootstrap.min.*). CSS source maps (bootstrap.*.map) are available for use with certain browsers' developer tools. Fonts from Glyphicons are included, as is the optional Bootstrap theme.
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:
The less/, js/, and fonts/ are the source code for our CSS, JS, and icon fonts (respectively). The dist/ folder includes everything listed in the precompiled download section above. The docs/ folder includes the source code for our documentation, and examples/ of Bootstrap usage. Beyond that, any other included file provides support for packages, license information, and development.
To install Grunt, you must first download and install node.js (which includes npm). npm stands for node packaged modules and is a way to manage development dependencies through node.js.
Compiles and minifies CSS and JavaScript, builds the documentation website, runs the HTML5 validator against the docs, regenerates the Customizer assets, and more. Requires Jekyll. Usually only necessary if you're hacking on Bootstrap itself.
Bootlint is the official Bootstrap HTML linter 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.
Alternative browsers which use the latest version of WebKit, Blink, or Gecko, whether directly or via the platform's web view API, are not explicitly supported. However, Bootstrap should (in most cases) display and function correctly in these browsers as well. More specific support information is provided below.
Generally speaking, Bootstrap supports the latest versions of each major platform's default browsers. Note that proxy browsers (such as Opera Mini, Opera Mobile's Turbo mode, UC Browser Mini, Amazon Silk) are not supported.
Unofficially, Bootstrap should look and behave well enough in Chromium and Chrome for Linux, Firefox for Linux, and Internet Explorer 7, as well as Microsoft Edge, though they are not officially supported.
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, Internet Explorer 8 requires the use of Respond.js to enable media query support.
Due to browser security rules, Respond.js doesn't work with pages viewed via the file:// protocol (like when opening a local HTML file). To test responsive features in IE8, view your pages over HTTP(S). See the Respond.js docs for details.
IE8 has some issues with @font-face when combined with :before. 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. See issue #13863 for details.
Internet Explorer 10 doesn't differentiate device width from viewport width, 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:
However, this doesn't work for devices running Windows Phone 8 versions older than Update 3 (a.k.a. GDR3), as it causes such devices to show a mostly desktop view instead of narrow "phone" view. To address this, you'll need to include the following CSS and JavaScript to work around the bug.
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 .col-*-1 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:
As of iOS 9.3, while a modal is open, if the initial touch of a scroll gesture is within the boundary of a textual or a , the content underneath the modal will be scrolled instead of the modal itself. See WebKit bug #153856.
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 position: absolute 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.
The .dropdown-backdrop 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 any other element which will fire a click event in iOS).
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.
Even though real hovering isn't possible on most touchscreens, most mobile browsers emulate hovering support and make :hover "sticky". In other words, :hover styles start applying after tapping an element and only stop applying after the user taps some other element. This can cause Bootstrap's :hover states to become undesirably "stuck" on such browsers. Some mobile browsers also make :focus similarly sticky. There is currently no simple workaround for these issues other than removing such styles entirely.
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. See issue #12078 and Chrome bug #273306 for some details. Suggested workarounds:
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.
On elements, the Android stock browser will not display the side controls if there is a border-radius and/or border applied. (See this StackOverflow question for details.) Use the snippet of code below to remove the offending CSS and render the as an unstyled element on the Android stock browser. The user agent sniffing avoids interference with Chrome, Safari, and Mozilla browsers.
In order to provide the best possible experience to old and buggy browsers, Bootstrap uses CSS browser hacks 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.
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.
Some third party software, including Google Maps and Google Custom Search Engine, conflict with Bootstrap due to * box-sizing: border-box; , a rule which makes it so padding does not affect the final computed width of an element. Learn more about box model and sizing at CSS Tricks.
If your navigation contains many links and comes before the main content in the DOM, add a Skip to main content link before the navigation (for a simple explanation, see this A11Y Project article on skip navigation links). Using the .sr-only class will visually hide the skip link, and the .sr-only-focusable class will ensure that the link becomes visible once focused (for sighted keyboard users).
Due to long-standing shortcomings/bugs in Chrome (see issue 262171 in the Chromium bug tracker) and Internet Explorer (see this article on in-page links and focus order), you will need to make sure that the target of your skip link is at least programmatically focusable by adding tabindex="-1".
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 tabindex="-1" when they are clicked with the mouse) with #content:focus outline: none; .
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.
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