twbootstrap/site/content/docs/4.6/components/forms.md

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docs Forms Examples and usage guidelines for form control styles, layout options, and custom components for creating a wide variety of forms. components true

Overview

Bootstrap's form controls expand on [our Rebooted form styles]({{< docsref "/content/reboot#forms" >}}) with classes. Use these classes to opt into their customized displays for a more consistent rendering across browsers and devices.

Be sure to use an appropriate type attribute on all inputs (e.g., email for email address or number for numerical information) to take advantage of newer input controls like email verification, number selection, and more.

Here's a quick example to demonstrate Bootstrap's form styles. Keep reading for documentation on required classes, form layout, and more.

{{< example >}}

We'll never share your email with anyone else.
Submit {{< /example >}}

Form controls

Textual form controls—like <input>s, <select>s, and <textarea>s—are styled with the .form-control class. Included are styles for general appearance, focus state, sizing, and more.

Be sure to explore our custom forms to further style <select>s.

{{< example >}}

1 2 3 4 5
1 2 3 4 5
{{< /example >}}

For file inputs, swap the .form-control for .form-control-file.

{{< example >}}

{{< /example >}}

Sizing

Set heights using classes like .form-control-lg and .form-control-sm.

{{< example >}} {{< /example >}}

{{< example >}} Large select Default select Small select {{< /example >}}

Readonly

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 >}} {{< /example >}}

Readonly plain text

If you want to have <input readonly> elements in your form styled as plain text, use the .form-control-plaintext class to remove the default form field styling and preserve the correct margin and padding.

{{< example >}}

{{< /example >}}

{{< example >}}

Confirm identity {{< /example >}}

Range Inputs

Set horizontally scrollable range inputs using .form-control-range.

{{< example >}}

{{< /example >}}

Checkboxes and radios

Default checkboxes and radios are improved upon with the help of .form-check, a single class for both input types that improves the layout and behavior of their HTML elements. 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. The disabled attribute will apply a lighter color to help indicate the input's state.

Checkboxes and radio buttons support HTML-based form validation and provide concise, accessible labels. As such, our <input>s and <label>s are sibling elements as opposed to an <input> within a <label>. This is slightly more verbose as you must specify id and for attributes to relate the <input> and <label>.

Default (stacked)

By default, any number of checkboxes and radios that are immediate sibling will be vertically stacked and appropriately spaced with .form-check.

{{< example >}}

{{< /example >}}

{{< example >}}

{{< /example >}}

Inline

Group checkboxes or radios on the same horizontal row by adding .form-check-inline to any .form-check.

{{< example >}}

{{< /example >}}

{{< example >}}

{{< /example >}}

Without labels

Add .position-static to inputs within .form-check that don't have any label text. Remember to still provide some form of accessible name for assistive technologies (for instance, using aria-label).

{{< example >}}

{{< /example >}}

Layout

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. It provides a flexible class that encourages proper grouping of labels, controls, optional help text, and form validation messaging. By default it only applies margin-bottom, but it picks up additional styles in .form-inline as needed. Use it with <fieldset>s, <div>s, or nearly any other element.

{{< example >}}

{{< /example >}}

Form grid

More complex forms can be built using our grid classes. Use these for form layouts that require multiple columns, varied widths, and additional alignment options.

{{< example >}}

{{< /example >}}

Form row

You may also swap .row for .form-row, a variation of our standard grid row that overrides the default column gutters for tighter and more compact layouts.

{{< example >}}

{{< /example >}}

More complex layouts can also be created with the grid system.

{{< example >}}

Choose... ...
Sign in {{< /example >}}

Horizontal form

Create horizontal forms with the grid by adding the .row class to form groups and using the .col-*-* classes to specify the width of your labels and controls. Be sure to add .col-form-label to your <label>s as well so they're vertically centered with their associated form controls.

At times, you maybe need to use margin or padding utilities to create that perfect alignment you need. For example, we've removed the padding-top on our stacked radio inputs label to better align the text baseline.

{{< example >}}

Radios
Sign in
{{< /example >}}
Horizontal form label sizing

Be sure to use .col-form-label-sm or .col-form-label-lg to your <label>s or <legend>s to correctly follow the size of .form-control-lg and .form-control-sm.

{{< example >}}

{{< /example >}}

Column sizing

As shown in the previous examples, our grid system allows you to place any number of .cols within a .row or .form-row. They'll split the available width equally between them. You may also pick a subset of your columns to take up more or less space, while the remaining .cols equally split the rest, with specific column classes like .col-7.

{{< example >}}

{{< /example >}}

Auto-sizing

The example below uses a flexbox utility to vertically center the contents and changes .col to .col-auto so that your columns only take up as much space as needed. Put another way, the column sizes itself based on the contents.

{{< example >}}

@
Submit
{{< /example >}}

You can then remix that once again with size-specific column classes.

{{< example >}}

@
Submit
{{< /example >}}

And of course custom form controls are supported.

{{< example >}}

Choose... One Two Three
Submit
{{< /example >}}

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 vary slightly from their default states.

  • Controls are display: flex, collapsing any HTML white space and allowing you to provide alignment control with [spacing]({{< docsref "/utilities/spacing" >}}) and [flexbox]({{< docsref "/utilities/flex" >}}) utilities.
  • Controls and input groups receive width: auto to override the Bootstrap default width: 100%.
  • Controls only appear inline in viewports that are at least 576px wide to account for narrow viewports on mobile devices.

You may need to manually address the width and alignment of individual form controls with [spacing utilities]({{< docsref "/utilities/spacing" >}}) (as shown below). Lastly, be sure to always include a <label> with each form control, even if you need to hide it from non-screenreader visitors with .sr-only.

{{< example >}}

@

Submit

{{< /example >}}

Custom form controls and selects are also supported.

{{< example >}}

Choose... One Two Three

Submit

{{< /example >}}

{{< callout warning >}}

Alternatives to hidden labels

Assistive technologies such as 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 .sr-only class. There are further alternative methods of providing a label for assistive technologies, such as the aria-label, aria-labelledby or title attribute. If none of these are present, assistive technologies may resort to using the placeholder attribute, if present, but note that use of placeholder as a replacement for other labelling methods is not advised. {{< /callout >}}

Help text

Block-level help text in forms can be created using .form-text (previously known as .help-block in v3). Inline help text can be flexibly implemented using any inline HTML element and utility classes like .text-muted.

{{< 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. {{< /callout >}}

Help text below inputs can be styled with .form-text. This class includes display: block and adds some top margin for easy spacing from the inputs above.

{{< example >}} Your password must be 8-20 characters long, contain letters and numbers, and must not contain spaces, special characters, or emoji. {{< /example >}}

Inline text can use any typical inline HTML element (be it a <small>, <span>, or something else) with nothing more than a utility class.

{{< example >}}

Must be 8-20 characters long.
{{< /example >}}

Disabled forms

Add the disabled boolean attribute on an input to prevent user interactions and make it appear lighter.

<input class="form-control" id="disabledInput" type="text" placeholder="Disabled input here..." disabled>

Add the disabled attribute to a <fieldset> to disable all the controls within.

{{< example >}}

Disabled fieldset example
Disabled select
Submit {{< /example >}}

{{< callout warning >}}

Caveat with anchors

Browsers 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 custom button-like elements such as <a ... class="btn btn-*">, these will only be given a style of pointer-events: none. As noted in the section about [disabled state for buttons]({{< docsref "/components/buttons#disabled-state" >}}) (and specifically in the sub-section for anchor elements), this CSS property is not yet standardized and isn't fully supported in Internet Explorer 10. The anchor-based controls will also still be focusable and operable using the keyboard. You must manually modify these controls by adding tabindex="-1" to prevent them from receiving focus and aria-disabled="disabled" to signal their state to assistive technologies. {{< /callout >}}

{{< 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. {{< /callout >}}

Validation

Provide valuable, actionable feedback to your users with HTML5 form validationavailable in all our supported browsers. Choose from the browser default validation feedback, or implement custom messages with our built-in classes and starter JavaScript.

{{< callout warning >}} We are aware that currently the client-side custom validation styles and tooltips are not accessible, since they are not exposed to assistive technologies. While we work on a solution, we'd recommend either using the server-side option or the default browser validation method. {{< /callout >}}

How it works

Here's how form validation works with Bootstrap:

  • HTML form validation is applied via CSS's two pseudo-classes, :invalid and :valid. It applies to <input>, <select>, and <textarea> elements.
  • Bootstrap scopes the :invalid and :valid styles to parent .was-validated class, usually applied to the <form>. Otherwise, any required field without a value shows up as invalid on page load. This way, you may choose when to activate them (typically after form submission is attempted).
  • To reset the appearance of the form (for instance, in the case of dynamic form submissions using AJAX), remove the .was-validated class from the <form> again after submission.
  • As a fallback, .is-invalid and .is-valid classes may be used instead of the pseudo-classes for server side validation. They do not require a .was-validated parent class.
  • Due to constraints in how CSS works, we cannot (at present) apply styles to a <label> that comes before a form control in the DOM without the help of custom JavaScript.
  • All modern browsers support the constraint validation API, a series of JavaScript methods for validating form controls.
  • Feedback messages may utilize the browser defaults (different for each browser, and unstylable via CSS) or our custom feedback styles with additional HTML and CSS.
  • You may provide custom validity messages with setCustomValidity in JavaScript.

With that in mind, consider the following demos for our custom form validation styles, optional server side classes, and browser defaults.

Custom styles

For custom Bootstrap form validation messages, you'll need to add the novalidate boolean attribute to your <form>. This disables the browser default feedback tooltips, but still provides access to the form validation APIs in JavaScript. Try to submit the form below; our JavaScript will intercept the submit button and relay feedback to you. When attempting to submit, you'll see the :invalid and :valid styles applied to your form controls.

Custom feedback styles apply custom colors, borders, focus styles, and background icons to better communicate feedback. Background icons for <select>s are only available with .custom-select, and not .form-control.

{{< example >}}

Looks good!
Looks good!
Please provide a valid city.
Choose... ...
Please select a valid state.
Please provide a valid zip.
You must agree before submitting.
Submit form

{{< /example >}}

Browser defaults

Not interested in custom validation feedback messages or writing JavaScript to change form behaviors? All good, you can use the browser defaults. Try submitting the form below. Depending on your browser and OS, you'll see a slightly different style of feedback.

While these feedback styles cannot be styled with CSS, you can still customize the feedback text through JavaScript.

{{< example >}}

Choose... ...
Submit form {{< /example >}}

Server side

We recommend using client-side validation, but in case you require server-side validation, you can indicate invalid and valid form fields with .is-invalid and .is-valid. Note that .invalid-feedback is also supported with these classes.

For invalid fields, ensure that the invalid feedback/error message is associated with the relevant form field using aria-describedby. This attribute allows more than one id to be referenced, in case the field already points to additional form text.

{{< example >}}

Looks good!
Looks good!
Please provide a valid city.
Choose... ...
Please select a valid state.
Please provide a valid zip.
You must agree before submitting.
Submit form {{< /example >}}

Supported elements

Validation styles are available for the following form controls and components:

  • <input>s and <textarea>s with .form-control
  • <select>s with .form-control or .custom-select
  • .form-checks
  • .custom-checkboxs and .custom-radios
  • .custom-file

{{< example >}}

Please enter a message in the textarea.
Example invalid feedback text
More example invalid feedback text
Choose... One Two Three
Example invalid custom select feedback
Example invalid custom file feedback
@
Example invalid input group feedback
Choose... One Two Three
Example invalid input group feedback
Button
Example invalid input group feedback
{{< /example >}}

Tooltips

If your form layout allows it, you can swap the .{valid|invalid}-feedback classes for .{valid|invalid}-tooltip classes to display validation feedback in a styled tooltip. Be sure to have a parent with position: relative on it for tooltip positioning. In the example below, our column classes have this already, but your project may require an alternative setup.

{{< example >}}

Looks good!
Looks good!
Please provide a valid city.
Choose... ...
Please select a valid state.
Please provide a valid zip.
Submit form {{< /example >}}

Customizing

Validation states can be customized via Sass with the $form-validation-states map. Located in our _variables.scss file, this Sass map is looped over to generate the default valid/invalid validation states. Included is a nested map for customizing each state's color and icon. While no other states are supported by browsers, those using custom styles can easily add more complex form feedback.

Please note that we do not recommend customizing these values without also modifying the form-validation-state mixin.

// Sass map from `_variables.scss`
// Override this and recompile your Sass to generate different states
$form-validation-states: map-merge(
  (
    "valid": (
      "color": $form-feedback-valid-color,
      "icon": $form-feedback-icon-valid
    ),
    "invalid": (
      "color": $form-feedback-invalid-color,
      "icon": $form-feedback-icon-invalid
    )
  ),
  $form-validation-states
);

// Loop from `_forms.scss`
// Any modifications to the above Sass map will be reflected in your compiled
// CSS via this loop.
@each $state, $data in $form-validation-states {
  @include form-validation-state($state, map-get($data, color), map-get($data, icon));
}

Input group validation

To detect what elements need rounded corners inside an input group with validation, an input group requires an additional .has-validation class.

<div class="input-group has-validation">
  <div class="input-group-prepend">
    <span class="input-group-text">@</span>
  </div>
  <input type="text" class="form-control" required>
  <div class="invalid-feedback">
    Please choose a username.
  </div>
</div>
@
Please choose a username.

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 <input> and <label> pairing is wrapped in a <div> to create our custom control. Structurally, this is the same approach as our default .form-check.

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-label class, we can also style the text for each item based on the <input>'s state.

We hide the default <input> with opacity and use the .custom-control-label to build a new custom form indicator in its place with ::before and ::after. Unfortunately we can't build a custom one from just the <input> because CSS's content doesn't work on that element.

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 >}}

{{< /example >}}

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:

$('.your-checkbox').prop('indeterminate', true)

Radios

{{< example >}}

{{< /example >}}

Inline

{{< example >}}

{{< /example >}}

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 >}}

{{< /example >}}

Switches

A switch has the markup of a custom checkbox but uses the .custom-switch class to render a toggle switch. Switches also support the disabled attribute.

{{< example >}}

{{< /example >}}

Select menu

Custom <select> menus need only a custom class, .custom-select to trigger the custom styles. Custom styles are limited to the <select>'s initial appearance and cannot modify the <option>s due to browser limitations.

{{< example >}} Open this select menu One Two Three {{< /example >}}

You may also choose from small and large custom selects to match our similarly sized text inputs.

{{< example >}} Open this select menu One Two Three Open this select menu One Two Three {{< /example >}}

The multiple attribute is also supported:

{{< example >}} Open this select menu One Two Three {{< /example >}}

As is the size attribute:

{{< example >}} Open this select menu One Two Three {{< /example >}}

Range

Create custom <input type="range"> controls with .custom-range. The track (the background) and thumb (the value) are both styled to appear the same across browsers. As only IE and Firefox support "filling" their track from the left or right of the thumb as a means to visually indicate progress, we do not currently support it.

{{< example >}} {{< /example >}}

Range inputs have implicit values for min and max0 and 100, respectively. You may specify new values for those using the min and max attributes.

{{< example >}} {{< /example >}}

By default, range inputs "snap" to integer values. To change this, you can specify a step value. In the example below, we double the number of steps by using step="0.5".

{{< example >}} {{< /example >}}

File browser

{{< callout info >}} The recommended plugin to animate custom file input: bs-custom-file-input, that's what we are using currently here in our docs. {{< /callout >}}

The file input is the most gnarly of the bunch and requires additional JavaScript if you'd like to hook them up with functional Choose file... and selected file name text.

{{< example >}}

{{< /example >}}

We hide the default file <input> via opacity and instead style the <label>. The button is generated and positioned with ::after. Lastly, we declare a width and height on the <input> for proper spacing for surrounding content.

Translating or customizing the strings with SCSS

The :lang() pseudo-class is used to allow for translation of the "Browse" text into other languages. Override or add entries to the $custom-file-text Sass 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):

$custom-file-text: (
  en: "Browse",
  es: "Elegir"
);

Here's lang(es) in action on the custom file input for a Spanish translation:

{{< example >}}

{{< /example >}}

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 on the <html> element or the Content-Language HTTP header, among other methods.

Translating or customizing the strings with HTML

Bootstrap also provides a way to translate the "Browse" text in HTML with the data-browse attribute which can be added to the custom input label (example in Dutch):

{{< example >}}

{{< /example >}}