Floating Labels ^commun

Méthode alternative d'affichage des labels à l'intérieur des input / select / textarea.
On enveloppe le tout dans une div avec la classe .form-floating.
A noter que l'élément de formulaire doit être en premier dans le DOM (avant le label).
A noter également que le contenu du placeholder ne sera plus affiché, seul le label le sera.

<div class="form-floating mb-3">
    <input type="email" class="form-control" id="floatingInput" placeholder="name@example.com">
    <label for="floatingInput">Email address</label>
</div>
<div class="form-floating">
    <input type="password" class="form-control" id="floatingPassword" placeholder="Password">
    <label for="floatingPassword">Password</label>
</div>

Lorsqu'une valeur est définie, les label seront décalés à leur position haute automatiquement.

<form class="form-floating">
    <input type="email" class="form-control" id="floatingInputValue" placeholder="name@example.com" value="test@example.com">
    <label for="floatingInputValue">Input with value</label>
</form>

Et à noter que les styles de validation fonctionnent correctement.

<form class="form-floating">
    <input type="email" class="form-control is-invalid" id="floatingInputInvalid" placeholder="name@example.com" value="test@example.com">
    <label for="floatingInputInvalid">Invalid input</label>
</form>

Par défaut, les textarea ayant le .form-control auront la hauteur d'un input.

<div class="form-floating">
    <textarea class="form-control" placeholder="Leave a comment here" id="floatingTextarea"></textarea>
    <label for="floatingTextarea">Comments</label>
</div>

<div class="form-floating">
    <textarea class="form-control" placeholder="Leave a comment here" id="floatingTextarea2" style="height: 100px"></textarea>
    <label for="floatingTextarea2">Comments</label>
</div>

À noter que les listes déroulantes multiples et size ne sont pas prises en charge.

<div class="form-floating">
    <select class="form-select" id="floatingSelect" aria-label="Floating label select example">
        <option selected>Open this select menu</option>
        <option value="1">One</option>
        <option value="2">Two</option>
        <option value="3">Three</option>
    </select>
    <label for="floatingSelect">Works with selects</label>
</div>

<div class="form-floating mb-3">
    <input type="email" class="form-control" id="floatingInputDisabled" placeholder="name@example.com" disabled>
    <label for="floatingInputDisabled">Email address</label>
</div>
<div class="form-floating mb-3">
    <textarea class="form-control" placeholder="Leave a comment here" id="floatingTextareaDisabled" disabled></textarea>
    <label for="floatingTextareaDisabled">Comments</label>
</div>
<div class="form-floating mb-3">
    <textarea class="form-control" placeholder="Leave a comment here" id="floatingTextarea2Disabled" style="height: 100px" disabled>Disabled textarea with some text inside</textarea>
    <label for="floatingTextarea2Disabled">Comments</label>
</div>
<div class="form-floating">
    <select class="form-select" id="floatingSelectDisabled" aria-label="Floating label disabled select example" disabled>
        <option selected>Open this select menu</option>
        <option value="1">One</option>
        <option value="2">Two</option>
        <option value="3">Three</option>
    </select>
    <label for="floatingSelectDisabled">Works with selects</label>
</div>

Les labels flottants prennent .form-control-plaintext.

<div class="form-floating mb-3">
    <input type="email" readonly class="form-control-plaintext" id="floatingEmptyPlaintextInput" placeholder="name@example.com">
    <label for="floatingEmptyPlaintextInput">Empty input</label>
</div>
<div class="form-floating mb-3">
    <input type="email" readonly class="form-control-plaintext" id="floatingPlaintextInput" placeholder="name@example.com" value="name@example.com">
    <label for="floatingPlaintextInput">Input with value</label>
</div>

Les labels flottants prennent en charge les .input-group.

<div class="input-group mb-3">
    <span class="input-group-text">@</span>
    <div class="form-floating">
        <input type="text" class="form-control" id="floatingInputGroup1" placeholder="Username">
        <label for="floatingInputGroup1">Username</label>
    </div>
</div>

<div class="input-group has-validation">
    <span class="input-group-text">@</span>
    <div class="form-floating is-invalid">
        <input type="text" class="form-control is-invalid" id="floatingInputGroup2" placeholder="Username" required>
        <label for="floatingInputGroup2">Username</label>
    </div>
    <div class="invalid-feedback">
        Please choose a username.
    </div>
</div>

<div class="row g-2">
    <div class="col-md">
        <div class="form-floating">
            <input type="email" class="form-control" id="floatingInputGrid" placeholder="name@example.com" value="mdo@example.com">
            <label for="floatingInputGrid">Email address</label>
        </div>
    </div>
    <div class="col-md">
        <div class="form-floating">
            <select class="form-select" id="floatingSelectGrid">
                <option selected>Open this select menu</option>
                <option value="1">One</option>
                <option value="2">Two</option>
                <option value="3">Three</option>
            </select>
            <label for="floatingSelectGrid">Works with selects</label>
        </div>
    </div>
</div>

$form-floating-height:                  add(3.5rem, $input-height-border);
$form-floating-line-height:             1.25;
$form-floating-padding-x:               $input-padding-x;
$form-floating-padding-y:               1rem;
$form-floating-input-padding-t:         1.625rem;
$form-floating-input-padding-b:         .625rem;
$form-floating-label-height:            1.5em;
$form-floating-label-opacity:           .65;
$form-floating-label-transform:         scale(.85) translateY(-.5rem) translateX(.15rem);
$form-floating-label-disabled-color:    $gray-600;
$form-floating-transition:              opacity .1s ease-in-out, transform .1s ease-in-out;