forms.md

  </div>

  <div class="custom-control custom-radio">
    <input type="radio" class="custom-control-input" id="customControlValidation2" name="radio-stacked" required>
    <label class="custom-control-label" for="customControlValidation2">Toggle this custom radio</label>
  </div>
  <div class="custom-control custom-radio mb-3">
    <input type="radio" class="custom-control-input" id="customControlValidation3" name="radio-stacked" required>
    <label class="custom-control-label" for="customControlValidation3">Or toggle this other custom radio</label>
    <div class="invalid-feedback">More example invalid feedback text</div>
  </div>

  <div class="form-group">
    <select class="custom-select" required>
      <option value="">Open this select menu</option>
      <option value="1">One</option>
      <option value="2">Two</option>
      <option value="3">Three</option>
    </select>
    <div class="invalid-feedback">Example invalid custom select feedback</div>
  </div>

  <div class="custom-file">
    <input type="file" class="custom-file-input" id="validatedCustomFile" required>
    <label class="custom-file-label" for="validatedCustomFile">Choose file...</label>
    <div class="invalid-feedback">Example invalid custom file feedback</div>
  </div>
</form>
{% endcapture %}
{% include example.html content=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.

{% capture example %}
<form class="needs-validation" novalidate>
  <div class="form-row">
    <div class="col-md-4 mb-3">
      <label for="validationTooltip01">First name</label>
      <input type="text" class="form-control" id="validationTooltip01" placeholder="First name" value="Mark" required>
      <div class="valid-tooltip">
        Looks good!
      </div>
    </div>
    <div class="col-md-4 mb-3">
      <label for="validationTooltip02">Last name</label>
      <input type="text" class="form-control" id="validationTooltip02" placeholder="Last name" value="Otto" required>
      <div class="valid-tooltip">
        Looks good!
      </div>
    </div>
    <div class="col-md-4 mb-3">
      <label for="validationTooltipUsername">Username</label>
      <div class="input-group">
        <div class="input-group-prepend">
          <span class="input-group-text" id="validationTooltipUsernamePrepend">@</span>
        </div>
        <input type="text" class="form-control" id="validationTooltipUsername" placeholder="Username" aria-describedby="validationTooltipUsernamePrepend" required>
        <div class="invalid-tooltip">
          Please choose a unique and valid username.
        </div>
      </div>
    </div>
  </div>
  <div class="form-row">
    <div class="col-md-6 mb-3">
      <label for="validationTooltip03">City</label>
      <input type="text" class="form-control" id="validationTooltip03" placeholder="City" required>
      <div class="invalid-tooltip">
        Please provide a valid city.
      </div>
    </div>
    <div class="col-md-3 mb-3">
      <label for="validationTooltip04">State</label>
      <input type="text" class="form-control" id="validationTooltip04" placeholder="State" required>
      <div class="invalid-tooltip">
        Please provide a valid state.
      </div>
    </div>
    <div class="col-md-3 mb-3">
      <label for="validationTooltip05">Zip</label>
      <input type="text" class="form-control" id="validationTooltip05" placeholder="Zip" required>
      <div class="invalid-tooltip">
        Please provide a valid zip.
      </div>
    </div>
  </div>
  <button class="btn btn-primary" type="submit">Submit form</button>
</form>
{% endcapture %}
{% include example.html content=example %}

## 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 `<div>` with a sibling `<span>` to create our custom control and a `<label>` for the accompanying text. 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](https://useiconic.com/open). This provides us the best control for styling and positioning across browsers and devices.

#### Checkboxes

{% capture example %}
<div class="custom-control custom-checkbox">
  <input type="checkbox" class="custom-control-input" id="customCheck1">
  <label class="custom-control-label" for="customCheck1">Check this custom checkbox</label>
</div>
{% endcapture %}
{% include example.html content=example %}

Custom checkboxes can also utilize the `:indeterminate` pseudo class when manually set via JavaScript (there is no available HTML attribute for specifying it).

<div class="bd-example bd-example-indeterminate">
  <div class="custom-control custom-checkbox">
    <input type="checkbox" class="custom-control-input" id="customCheck2">
    <label class="custom-control-label" for="customCheck2">Check this custom checkbox</label>
  </div>
</div>

If you're using jQuery, something like this should suffice:

{% highlight js %}
$('.your-checkbox').prop('indeterminate', true)
{% endhighlight %}

#### Radios

{% capture example %}
<div class="custom-control custom-radio">
  <input type="radio" id="customRadio1" name="customRadio" class="custom-control-input">
  <label class="custom-control-label" for="customRadio1">Toggle this custom radio</label>
</div>
<div class="custom-control custom-radio">
  <input type="radio" id="customRadio2" name="customRadio" class="custom-control-input">
  <label class="custom-control-label" for="customRadio2">Or toggle this other custom radio</label>
</div>
{% endcapture %}
{% include example.html content=example %}

#### Inline

{% capture example %}
<div class="custom-control custom-radio custom-control-inline">
  <input type="radio" id="customRadioInline1" name="customRadioInline1" class="custom-control-input">
  <label class="custom-control-label" for="customRadioInline1">Toggle this custom radio</label>
</div>
<div class="custom-control custom-radio custom-control-inline">
  <input type="radio" id="customRadioInline2" name="customRadioInline1" class="custom-control-input">
  <label class="custom-control-label" for="customRadioInline2">Or toggle this other custom radio</label>
</div>
{% endcapture %}
{% include example.html content=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.

{% capture example %}
<div class="custom-control custom-checkbox">
  <input type="checkbox" class="custom-control-input" id="customCheckDisabled" disabled>
  <label class="custom-control-label" for="customCheckDisabled">Check this custom checkbox</label>
</div>

<div class="custom-control custom-radio">
  <input type="radio" id="radio3" name="radioDisabled" id="customRadioDisabled" class="custom-control-input" disabled>
  <label class="custom-control-label" for="customRadioDisabled">Toggle this custom radio</label>
</div>
{% endcapture %}
{% include example.html content=example %}

### Select menu

Custom `<select>` menus need only a custom class, `.custom-select` to trigger the custom styles.

{% capture example %}
<select class="custom-select">
  <option selected>Open this select menu</option>
  <option value="1">One</option>
  <option value="2">Two</option>
  <option value="3">Three</option>
</select>
{% endcapture %}
{% include example.html content=example %}

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

{% capture example %}
<select class="custom-select custom-select-lg mb-3">
  <option selected>Open this select menu</option>
  <option value="1">One</option>
  <option value="2">Two</option>
  <option value="3">Three</option>
</select>

<select class="custom-select custom-select-sm">
  <option selected>Open this select menu</option>
  <option value="1">One</option>
  <option value="2">Two</option>
  <option value="3">Three</option>
</select>
{% endcapture %}
{% include example.html content=example %}

The `multiple` attribute is also supported:

{% capture example %}
<select class="custom-select" multiple>
  <option selected>Open this select menu</option>
  <option value="1">One</option>
  <option value="2">Two</option>
  <option value="3">Three</option>
</select>
{% endcapture %}
{% include example.html content=example %}

As is the `size` attribute:

{% capture example %}
<select class="custom-select" size="3">
  <option selected>Open this select menu</option>
  <option value="1">One</option>
  <option value="2">Two</option>
  <option value="3">Three</option>
</select>
{% endcapture %}
{% include example.html content=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.

{% capture example %}
<label for="customRange1">Example range</label>
<input type="range" class="custom-range" id="customRange1">
{% endcapture %}
{% include example.html content=example %}

Range inputs have implicit values for `min` and `max`—`0` and `100`, respectively. You may specify new values for those using the `min` and `max` attributes.

{% capture example %}
<label for="customRange2">Example range</label>
<input type="range" class="custom-range" min="0" max="5" id="customRange2">
{% endcapture %}
{% include example.html content=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"`.

{% capture example %}
<label for="customRange3">Example range</label>
<input type="range" class="custom-range" min="0" max="5" step="0.5" id="customRange3">
{% endcapture %}
{% include example.html content=example %}

### File browser

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.

{% capture example %}
<div class="custom-file">
  <input type="file" class="custom-file-input" id="customFile">
  <label class="custom-file-label" for="customFile">Choose file</label>
</div>
{% endcapture %}
{% include example.html content=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

The [`:lang()` pseudo-class](https://developer.mozilla.org/en-US/docs/Web/CSS/:lang) 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](https://en.wikipedia.org/wiki/IETF_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: (
  en: "Browse",
  es: "Elegir"
);
{% endhighlight %}

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

{% capture example %}
<div class="custom-file">
  <input type="file" class="custom-file-input" id="customFileLang" lang="es">
  <label class="custom-file-label" for="customFileLang">Seleccionar Archivo</label>
</div>
{% endcapture %}
{% include example.html content=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](https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/lang) on the `<html>` element or the [`Content-Language` HTTP header](https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.12), among other methods.