<p>When using tooltips or popovers on elements within a <code>.btn-group</code>, you'll have to specify the option <code>container: 'body'</code> to avoid unwanted side effects (such as the element growing wider and/or losing its rounded corners when the tooltip or popover is triggered).</p>
</div>
<divclass="bs-callout bs-callout-warning">
<h4>Ensure correct <code>role</code> and provide a label</h4>
<p>In order for assistive technologies – such as screen readers – to convey that a series of buttons is grouped, an appropriate <code>role</code> attribute needs to be provided. For button groups, this would be <code>role="group"</code>, while toolbars should have a <code>role="toolbar"</code>.</p>
<p>One exception are groups which only contain a single control (for instance the <ahref="#btn-groups-justified">justified button groups</a> with <code><button></code> elements) or a dropdown.</p>
<p>In addition, groups and toolbars should be given an explicit label, as most assistive technologies will otherwise not announce them, despite the presence of the correct <code>role</code> attribute. In the examples provided here, we use <code>aria-label</code>, but alternatives such as <code>aria-labelledby</code> can also be used.</p>
</div>
<h3id="btn-groups-single">Basic example</h3>
<p>Wrap a series of buttons with <code>.btn</code> in <code>.btn-group</code>.</p>
<p>Make a set of buttons appear vertically stacked rather than horizontally. <strongclass="text-danger">Split button dropdowns are not supported here.</strong></p>
<p>If the <code><a></code> elements are used to act as buttons – triggering in-page functionality, rather than navigating to another document or section within the current page – they should also be given an appropriate <code>role="button"</code>.</p>
<p>To use justified button groups with <code><button></code> elements, <strongclass="text-danger">you must wrap each button in a button group</strong>. Most browsers don't properly apply our CSS for justification to <code><button></code> elements, but since we support button dropdowns, we can workaround that.</p>
<p>To use justified button groups with <code><button></code> elements, <strongclass="text-danger">you must wrap each button in a button group</strong>. Most browsers don't properly apply our CSS for justification to <code><button></code> elements, but since we support button dropdowns, we can workaround that.</p>
<p>Wrap the dropdown's trigger and the dropdown menu within <code>.dropdown</code>, or another element that declares <code>position: relative;</code>. Then add the menu's HTML.</p>
<pclass="lead">Navs available in Bootstrap have shared markup, starting with the base <code>.nav</code> class, as well as shared states. Swap modifier classes to switch between each style.</p>
<divclass="bs-callout bs-callout-info">
<h4>Using navs for tab panels requires JavaScript tabs plugin</h4>
<p>For tabs with tabbable areas, you must use the <ahref="../javascript/#tabs">tabs JavaScript plugin</a>. The markup will also require additional <code>role</code> and ARIA attributes – see the plugin's <ahref="../javascript/#tabs-usage">example markup</a> for further details.</p>
</div>
<divclass="bs-callout bs-callout-warning">
<h4>Make navs used as navigation accessible</h4>
<p>If you are using navs to provide a navigation bar, be sure to add a <code>role="navigation"</code> to the most logical parent container of the <code><ul></code>, or wrap a <code><nav></code> element around the whole navigation. Do not add the role to the <code><ul></code> itself, as this would prevent it from being announced as an actual list by assistive technologies.</p>
</div>
<h2id="nav-tabs">Tabs</h2>
<p>Note the <code>.nav-tabs</code> class requires the <code>.nav</code> base class.</p>
<p>As of v8.0, Safari exhibits a bug in which resizing your browser horizontally causes rendering errors in the justified nav that are cleared upon refreshing. This bug is also shown in the <ahref="../examples/justified-nav/">justified nav example</a>.</p>
<p>You can optionally swap out active or disabled anchors for <code><span></code> to remove click functionality while retaining intended styles.</p>
<p>You can optionally swap out active or disabled anchors for <code><span></code>, or omit the anchor in the case of the previous/next arrows, to remove click functionality while retaining intended styles.</p>
<h4>Conveying meaning to assistive technologies</h4>
<p>Using color to add meaning to a button only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the content itself (the visible text of the button), or is included through alternative means, such as additional text hidden with the <code>sr-only</code> class.</p>
</div>
<h2id="buttons-sizes">Sizes</h2>
<p>Fancy larger or smaller buttons? Add <code>.btn-lg</code>, <code>.btn-sm</code>, or <code>.btn-xs</code> for additional sizes.</p>
<divclass="bs-example">
...
...
@@ -88,7 +93,7 @@
<h2id="buttons-active">Active state</h2>
<p>Buttons will appear pressed (with a darker background, darker border, and inset shadow) when active. For <code><button></code> elements, this is done via <code>:active</code>. For <code><a></code> elements, it's done with <code>.active</code>. However, you may use <code>.active</code> on <code><button></code>s should you need to replicate the active state programmatically.</p>
<p>Buttons will appear pressed (with a darker background, darker border, and inset shadow) when active. For <code><button></code> elements, this is done via <code>:active</code>. For <code><a></code> elements, it's done with <code>.active</code>. However, you may use <code>.active</code> on <code><button></code>s (and include the <code>aria-pressed="true"</code> attribute) should you need to replicate the active state programmatically.</p>
<h3>Button element</h3>
<p>No need to add <code>:active</code> as it's a pseudo-class, but if you need to force the same appearance, go ahead and add <code>.active</code>.</p>
...
...
@@ -147,7 +152,7 @@
</p>
<divclass="bs-callout bs-callout-warning">
<h4>Link functionality caveat</h4>
<p>This class uses <code>pointer-events: none</code> to try to disable the link functionality of <code><a></code>s, but that CSS property is not yet standardized and isn't fully supported in Opera 18 and below, or in Internet Explorer 11. So to be safe, use custom JavaScript to disable such links.</p>
<p>This class uses <code>pointer-events: none</code> to try to disable the link functionality of <code><a></code>s, but that CSS property is not yet standardized and isn't fully supported in Opera 18 and below, or in Internet Explorer 11. In addition, even in browsers that do support <code>pointer-events: none</code>, keyboard navigation remains unaffected, meaning that sighted keyboard users and users of assistive technologies will still be able to activate these links. So to be safe, use custom JavaScript to disable such links.</p>
<p>If the <code><a></code> elements are used to act as buttons – triggering in-page functionality, rather than navigating to another document or section within the current page – they should also be given an appropriate <code>role="button"</code>.</p>
</div>
<divclass="bs-callout bs-callout-warning">
<h4>Cross-browser rendering</h4>
<p>As a best practice, <strong>we highly recommend using the <code><button></code> element whenever possible</strong> to ensure matching cross-browser rendering.</p>
<p>Screen readers will have trouble with your forms if you don't include a label for every input. For these inline forms, you can hide the labels using the <code>.sr-only</code> class.</p>
<p>Screen readers will have trouble with your forms if you don't include a label for every input. For these inline forms, you can hide the labels using the <code>.sr-only</code> class. There are further alternative methods of providing a label for assistive technologies, such as the <code>aria-label</code>, <code>aria-labelledby</code> or <code>title</code> attribute. If none of these is present, screen readers may resort to using the <code>placeholder</code> attribute, if present, but note that use of <code>placeholder</code> as a replacement for other labelling methods is not advised.</p>
<p>Should you have no text within the <code><label></code>, the input is positioned as you'd expect. <strong>Currently only works on non-inline checkboxes and radios.</strong></p>
<h4>Checkboxes and radios without label text</h4>
<p>Should you have no text within the <code><label></code>, the input is positioned as you'd expect. <strong>Currently only works on non-inline checkboxes and radios.</strong> Remember to still provide some form of label for assistive technologies (for instance, using <code>aria-label</code>).</p>
<p>We remove the default <code>outline</code> styles on some form controls and apply a <code>box-shadow</code> in its place for <code>:focus</code>.</p>
<p>Bootstrap includes validation styles for error, warning, and success states on form controls. To use, add <code>.has-warning</code>, <code>.has-error</code>, or <code>.has-success</code> to the parent element. Any <code>.control-label</code>, <code>.form-control</code>, and <code>.help-block</code> within that element will receive the validation styles.</p>
<divclass="bs-callout bs-callout-warning">
<h4>Conveying validation state to assistive technologies</h4>
<p>Using these validation styles to denote the state of a form control only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers.</p>
<p>Ensure that an alternative indication of state is also provided. For instance, you can include a hint about state in the form control's <code><label></code> text itself (as is the case in the following code example), or associate an additional element with textual information about the validation state with the form control using <code>aria-describedby</code> (see the example in the following section). In the case of an error, you could also use the <code>aria-invalid="true"</code> attribute on the form control.</p>
</div>
<divclass="bs-example">
<formrole="form">
<divclass="form-group has-success">
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...
@@ -648,40 +651,45 @@
<h4>Icons, labels, and input groups</h4>
<p>Manual positioning of feedback icons is required for inputs without a label and for <ahref="../components#input-groups">input groups</a> with an add-on on the right. You are strongly encouraged to provide labels for all inputs for accessibility reasons. If you wish to prevent labels from being displayed, hide them with the <code>sr-only</code> class. If you must do without labels, adjust the <code>top</code> value of the feedback icon. For input groups, adjust the <code>right</code> value to an appropriate pixel value depending on the width of your addon.</p>
</div>
<divclass="bs-callout bs-callout-warning">
<h4>Conveying the icon's meaning to assistive technologies</h4>
<p>To ensure that assistive technologies – such as screen readers – correctly convey the meaning of an icon, additional hidden text should be included with the <code>sr-only</code> class, and the icon itself explicitly associated with the form control it relates to using <code>aria-describedby</code>. Alternatively, ensure that the meaning (for instance, the fact that there is a warning for a particular text entry field) is conveyed in some other form, such as changing the text of the actual <code><label></code> associated with the form control.</p>
<p>Although the following examples already mention the validation state of their respective form controls in the <code><label></code> text itself, the above technique (using <code>sr-only</code> text and <code>aria-describedby</code>) has been included for illustrative purposes.</p>
</div>
<divclass="bs-example">
<formrole="form">
<divclass="form-group has-success has-feedback">
<labelclass="control-label"for="inputSuccess2">Input with success</label>
<p>Help text should be explicitly associated with the form control it relates to using the <code>aria-describedby</code> attribute. This will ensure that assistive technologies – such as screen readers – will announce this help text when the user focuses or enters the control.</p>
</div>
<divclass="bs-example">
<formrole="form">
<inputtype="text"class="form-control">
<spanclass="help-block">A block of help text that breaks onto a new line and may extend beyond one line.</span>
<divclass="form-group">
<labelfor="inputHelpBlock">Input with help text</label>
<p>Sometimes emphasis classes cannot be applied due to the specificity of another selector. In most cases, a sufficient workaround is to wrap your text in a <code><span></code> with the class.</p>
</div>
<divclass="bs-callout bs-callout-warning">
<h4>Conveying meaning to assistive technologies</h4>
<p>Using color to add meaning only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the content itself (the contextual colors are only used to reinforce meaning that is already present in the text/markup), or is included through alternative means, such as additional text hidden with the <code>.sr-only</code> class.</p>
<p>Similar to the contextual text color classes, easily set the background of an element to any contextual class. Anchor components will darken on hover, just like the text classes.</p>
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...
@@ -44,6 +48,10 @@
<h4>Dealing with specificity</h4>
<p>Sometimes contextual background classes cannot be applied due to the specificity of another selector. In some cases, a sufficient workaround is to wrap your element's content in a <code><div></code> with the class.</p>
</div>
<divclass="bs-callout bs-callout-warning">
<h4>Conveying meaning to assistive technologies</h4>
<p>As with <ahref="#helper-classes-colors">contextual colors</a>, ensure that any meaning conveyed through color is also conveyed in a format that is not purely presentational.</p>
</div>
<h3id="helper-classes-close">Close icon</h3>
<p>Use the generic close icon for dismissing content like modals and alerts.</p>
<h4>Conveying meaning to assistive technologies</h4>
<p>Using color to add meaning to a table row or individual cell only provides a visual indication, which will not be conveyed to users of assistive technologies – such as screen readers. Ensure that information denoted by the color is either obvious from the content itself (the visible text in the relevant table row/cell), or is included through alternative means, such as additional text hidden with the <code>sr-only</code> class.</p>
</div>
<h2id="tables-responsive">Responsive tables</h2>
<p>Create responsive tables by wrapping any <code>.table</code> in <code>.table-responsive</code> to make them scroll horizontally on small devices (under 768px). When viewing on anything larger than 768px wide, you will not see any difference in these tables.</p>
<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>
<h3>Color contrast</h3>
<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>
<h3>Additional resources</h3>
<ul>
<li><ahref="https://github.com/squizlabs/HTML_CodeSniffer">"HTML Codesniffer" bookmarklet for identifying accessibility issues</a></li>
<p>You can activate a tab or pill navigation without writing any JavaScript by simply specifying <code>data-toggle="tab"</code> or <code>data-toggle="pill"</code> on an element. Adding the <code>nav</code> and <code>nav-tabs</code> classes to the tab <code>ul</code> will apply the Bootstrap <ahref="../components/#nav-tabs">tab styling</a>, while adding the <code>nav</code> and <code>nav-pills</code> classes will apply <ahref="../components/#nav-pills">pill styling</a>.</p>
