33 KiB
| layout | title | group |
|---|---|---|
| docs | Forms | components |
Bootstrap provides several form control styles, layout options, and custom components for creating a wide variety of forms.
Contents
- Will be replaced with the ToC, excluding the "Contents" header {:toc}
Form controls
Bootstrap's form controls expand on [our Rebooted form styles]({{ site.baseurl }}/content/reboot/#forms) with classes. Use these classes to opt into their customized displays for a more consistent rendering across browsers and devices. The example form below demonstrates common HTML form elements that receive updated styles from Bootstrap with additional classes.
Remember, since Bootstrap utilizes the HTML5 doctype, all inputs must have a type attribute.
{% example html %}
We'll never share your email with anyone else. 1 2 3 4 5 1 2 3 4 5 This is some placeholder block-level help text for the above input. It's a bit lighter and easily wraps to a new line.Below is a complete list of the specific form controls supported by Bootstrap and the classes that customize them. Additional documentation is available for each group.
| Classes | Used for | Supported variations |
|---|---|---|
| {% markdown %}`.form-group`{% endmarkdown %} | Any group of form controls |
{% markdown %}Use with any block-level element like `` or ` `{% endmarkdown %}
|
| {% markdown %}`.form-control`{% endmarkdown %} | Textual inputs | {% markdown %}`text`, `password`, `datetime-local`, `date`, `month`, `time`, `week`, `number`, `email`, `url`, `search`, `tel`, `color`{% endmarkdown %} |
| Select menus | {% markdown %}`multiple`, `size`{% endmarkdown %} | |
| Textareas | N/A | |
| {% markdown %}`.form-control-file`{% endmarkdown %} | File inputs | {% markdown %}`file`{% endmarkdown %} |
|
{% markdown %}
`.radio` `.radio-inline` `.checkbox` `.checkbox-inline` {% endmarkdown %} |
Checkboxes and radios | N/A |
Textual inputs
Here are examples of .form-control applied to each textual HTML5 <input> type.
{% example html %}
Form layouts
Since Bootstrap applies display: block and width: 100% to almost all our form controls, forms will by default stack vertically. Additional classes can be used to vary this layout on a per-form basis.
Form groups
The .form-group class is the easiest way to add some structure to forms. Its only purpose is to provide margin-bottom around a label and control pairing. As a bonus, since it's a class you can use it with <fieldset>s, <div>s, or nearly any other element.
{% example html %}
{% endexample %}Inline forms
Use the .form-inline class to display a series of labels, form controls, and buttons on a single horizontal row. Form controls within inline forms behave differently:
- Controls are
display: inline-blockto provide alignment control viavertical-alignandmargin. - Controls receive
width: autoto override the Bootstrap defaultwidth: 100%. - Controls only appear inline in viewports that are at least 768px wide to account for narrow viewports on mobile devices.
Because of this, you may need to manually address the width and alignment of individual form controls. Lastly, as shown below, you should always include a <label> with each form control.
Visible labels
{% example html %}
Hidden labels
{% example html %}
{% example html %}
Using the Grid
For more structured form layouts, you can utilize Bootstrap's predefined grid classes (or mixins) to create horizontal forms. Add the .row class to form groups and use the .col-*-* classes to specify the width of your labels and controls.
Be sure to add .form-control-label to your <label>s as well so they're vertically centered with their associated labels.
{% example html %}
Checkboxes and radios
Checkboxes are for selecting one or several options in a list, while radios are for selecting one option from many.
Disabled checkboxes and radios are supported, but to provide a "not-allowed" cursor on hover of the parent <label>, you'll need to add the .disabled class to the parent .radio, .radio-inline, .checkbox, or .checkbox-inline.
Default (stacked)
{% example html %}
Inline
Use the .checkbox-inline or .radio-inline classes on a series of checkboxes or radios for controls that appear on the same line.
{% example html %} 1 2 3 {% endexample %}
{% example html %} 1 2 3 {% endexample %}
Without labels
Should you have no text within the <label>, the input is positioned as you'd expect. Currently only works on non-inline checkboxes and radios.
{% example html %}
Static controls
When you need to place plain text next to a form label within a form, use the .form-control-static class on a <p>.
{% example html %}
{% example html %}
Disabled states
Add the disabled boolean attribute on an input to prevent user interactions. Disabled inputs appear lighter and add a not-allowed cursor.
{% highlight html %} {% endhighlight %}
Add the disabled attribute to a <fieldset> to disable all the controls within.
{% example html %}
{% callout warning %}
Caveat about link functionality of <a>
By default, browsers will treat all native form controls (<input>, <select> and <button> elements) inside a <fieldset disabled> as disabled, preventing both keyboard and mouse interactions on them. However, if your form also includes <a ... class="btn btn-*"> elements, these will only be given a style of pointer-events: none. As noted in the section about disabled state for buttons (and specifically in the sub-section for anchor elements), this CSS property is not yet standardized and isn't fully supported in Opera 18 and below, or in Internet Explorer 11, and won't prevent keyboard users from being able to focus or activate these links. So to be safe, use custom JavaScript to disable such links.
{% endcallout %}
{% callout danger %}
Cross-browser compatibility
While Bootstrap will apply these styles in all browsers, Internet Explorer 11 and below don't fully support the disabled attribute on a <fieldset>. Use custom JavaScript to disable the fieldset in these browsers.
{% endcallout %}
Readonly inputs
Add the readonly boolean attribute on an input to prevent modification of the input's value. Read-only inputs appear lighter (just like disabled inputs), but retain the standard cursor.
{% example html %} {% endexample %}
Control sizing
Set heights using classes like .form-control-lg, and set widths using grid column classes like .col-lg-*.
{% example html %} {% endexample %}
{% example html %} {% endexample %}
Column sizing
Wrap inputs in grid columns, or any custom parent element, to easily enforce desired widths.
{% example html %}
Help text
No official help text classes exist in Bootstrap 4 (previously we had .help-block in v3), but thanks to our utility classes like .text-muted, you can create much more flexible help text as you need it.
{% callout warning %}
Associating help text with form controls
Help text should be explicitly associated with the form control it relates to using the aria-describedby attribute. This will ensure that assistive technologies – such as screen readers – will announce this help text when the user focuses or enters the control.
{% endcallout %}
Inline text can use any typical inline HTML element (be it a <small>, <span>, or something else).
{% example html %}
Block help text—for below inputs or for longer lines of help text—can be easily achieved with a <p>.
{% example html %}
Your password must be 8-20 characters long, contain letters and numbers, and must not contain spaces, special characters or emoji.
{% endexample %}Validation
Bootstrap includes validation styles for danger, warning, and success states on form controls.
- To use, add
.has-warning,.has-danger, or.has-successto the parent element. Any.form-control-label,.form-control, and.text-helpwithin that element will receive the validation styles. - Validation icons are
url()s configured via Sass variables that are applied tobackground-imagedeclarations for each state. - You may use your own base64 PNGs or SVGs by updating the Sass variables and recompiling.
- Icons can also be disabled entirely by setting the variables to
noneor commenting out the source Sass.
{% comment %} {% callout warning %}
Conveying validation state to assistive technologies and colorblind users
Using these validation styles to denote the state of a form control only provides a visual, color-based indication, which will not be conveyed to users of assistive technologies - such as screen readers - or to colorblind users.
Ensure that an alternative indication of state is also provided. For instance, you can include a hint about state in the form control's <label> text itself (as is the case in the following code example), include a Glyphicon (with appropriate alternative text using the .sr-only class - see the Glyphicon examples), or by providing an additional help text block. Specifically for assistive technologies, invalid form controls can also be assigned an aria-invalid="true" attribute.
{% endcallout %}
{% endcomment %}
{% example html %}
Custom forms
For even more customization and cross browser consistency, use our completely custom form elements to replace the browser defaults. They're built on top of semantic and accessible markup, so they're solid replacements for any default form control.
Checkboxes and radios
Each checkbox and radio is wrapped in a <label> for three reasons:
- It provides a larger hit areas for checking the control.
- It provides a helpful and semantic wrapper to help us replace the default
<input>s. - It triggers the state of the
<input>automatically, meaning no JavaScript is required.
We hide the default <input> with opacity and use the .custom-control-indicator to build a new custom form indicator in its place. Unfortunately we can't build a custom one from just the <input> because CSS's content doesn't work on that element.
We use the sibling selector (~) for all our <input> states—like :checked—to properly style our custom form indicator. When combined with the .custom-control-description class, we can also style the text for each item based on the <input>'s state.
In the checked states, we use base64 embedded SVG icons from Open Iconic. This provides us the best control for styling and positioning across browsers and devices.
Checkboxes
{% example html %} Check this custom checkbox {% endexample %}
Custom checkboxes can also utilize the :indeterminate pseudo class when manually set via JavaScript (there is no available HTML attribute for specifying it).
If you're using jQuery, something like this should suffice:
{% highlight js %} $('.your-checkbox').prop('indeterminate', true) {% endhighlight %}
Radios
{% example html %} Toggle this custom radio Or toggle this other custom radio {% endexample %}
Disabled
Custom checkboxes and radios can also be disabled. Add the disabled boolean attribute to the <input> and the custom indicator and label description will be automatically styled.
{% example html %} Check this custom checkbox
Toggle this custom radio {% endexample %}Validation states
Add other states to your custom forms with our validation classes.
{% example html %}
Stacked
Custom checkboxes and radios are inline to start. Add a parent with class .custom-controls-stacked to ensure each form control is on separate lines.
{% example html %}
Select menu
Custom <select> menus need only a custom class, .custom-select to trigger the custom styles.
{% example html %} Open this select menu One Two Three {% endexample %}
Custom selects degrade nicely in IE9, receiving only a handful of overrides to remove the custom background-image. Multiple selects (e.g., <select multiple>) are not currently supported.
File browser
The file input is the most gnarly of the bunch and require additional JavaScript if you'd like to hook them up with functional Choose file... and selected file name text.
{% example html %} {% endexample %}
Here's how it works:
- We wrap the
<input>in a<label>so the custom control properly triggers the file browser. - We hide the default file
<input>viaopacity. - We use
:afterto generate a custom background and directive (Choose file...). - We use
:beforeto generate and position the Browse button. - We declare a
heighton the<input>for proper spacing for surrounding content.
In other words, it's an entirely custom element, all generated via CSS.
Translating or customizing the strings
The :lang() pseudo-class is used to allow for easy translation of the "Browse" and "Choose file..." text into other languages. Simply override or add entries to the $custom-file-text SCSS variable with the relevant language tag and localized strings. The English strings can be customized the same way. For example, here's how one might add a Spanish translation (Spanish's language code is es):
{% highlight scss %} $custom-file-text: ( placeholder: ( en: "Choose file...", es: "Seleccionar archivo..." ), button-label: ( en: "Browse", es: "Navegar" ) ); {% endhighlight %}
You'll need to set the language of your document (or subtree thereof) correctly in order for the correct text to be shown. This can be done using the lang attribute or the Content-Language HTTP header, among other methods.