Bootstrap4 forms 重點摘要

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一、基本 forms 範例

一個基本的 forms 範例為

<!doctype html>
<html lang="en">
<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

    <title>Hello, world!</title>
</head>
<body>
    <form>
        <div class="form-group">
            <label for="exampleInputEmail1">Email address</label>
            <input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp" placeholder="Enter email">
            <small id="emailHelp" class="form-text text-muted">We'll never share your email with anyone else.</small>
        </div>
        <div class="form-group">
            <label for="exampleInputPassword1">Password</label>
            <input type="password" class="form-control" id="exampleInputPassword1" placeholder="Password">
        </div>
        <div class="form-group form-check">
            <input type="checkbox" class="form-check-input" id="exampleCheck1">
            <label class="form-check-label" for="exampleCheck1">Check me out</label>
        </div>
        <button type="submit" class="btn btn-primary">Submit</button>
    </form>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
</body>
</html>

畫面如下

 

二、form-inline 樣式

<!doctype html>
<html lang="en">
<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

    <title>Hello, world!</title>
</head>
<body>
    <form class="form-inline">
        <div class="form-group mb-2">
            <label for="staticEmail2" class="sr-only">Email</label>
            <input type="text" readonly class="form-control-plaintext" id="staticEmail2" value="email@example.com">
        </div>
        <div class="form-group mx-sm-3 mb-2">
            <label for="inputPassword2" class="sr-only">Password</label>
            <input type="password" class="form-control" id="inputPassword2" placeholder="Password">
        </div>
        <button type="submit" class="btn btn-primary mb-2">Confirm identity</button>
    </form>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
</body>
</html>

在大於 576px 時，會保持 inline 樣式

 

三、Form grid 系統

1、.row 與 .form-row 樣式的差異

.row

<!doctype html>
<html lang="en">
<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

    <title>Hello, world!</title>
</head>
<body>
    <form>
        <div class="row">
            <div class="col">
                <input type="text" class="form-control" placeholder="First name">
            </div>
            <div class="col">
                <input type="text" class="form-control" placeholder="Last name">
            </div>
        </div>
    </form>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
</body>
</html>

畫面為

 

.form-row

<!doctype html>
<html lang="en">
<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

    <title>Hello, world!</title>
</head>
<body>
    <form>
        <div class="form-row">
            <div class="col">
                <input type="text" class="form-control" placeholder="First name">
            </div>
            <div class="col">
                <input type="text" class="form-control" placeholder="Last name">
            </div>
        </div>
    </form>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
</body>
</html>

畫面為

.form-row 會比 .row 的排列還要來的緊湊

 

2、注意 .form-row 所配的位置會造成兩者樣式的不同

<!doctype html>
<html lang="en">
<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

    <title>Hello, world!</title>
</head>
<body>
    <form>
        <div class="form-row">
            <div class="form-group col-sm-6">
                <label for="inputEmail4">Email</label>
                <input type="email" class="form-control" id="inputEmail4" placeholder="Email">
            </div>
            <div class="form-group col-sm-6">
                <label for="inputPassword4">Password</label>
                <input type="password" class="form-control" id="inputPassword4" placeholder="Password">
            </div>
        </div>
    </form>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
</body>
</html>

畫面為

 

<!doctype html>
<html lang="en">
<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

    <title>Hello, world!</title>
</head>
<body>
    <form>
        <div class="form-group form-row">
            <label class="col-sm-6" for="inputEmail4">Email</label>
            <input type="email" class="form-control col-sm-6" id="inputEmail4" placeholder="Email">
        </div>
        <div class="form-group form-row">
            <label class="col-sm-6" for="inputPassword4">Password</label>
            <input type="password" class="form-control col-sm-6" id="inputPassword4" placeholder="Password">
        </div>
    </form>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
</body>
</html>

畫面為

 

四、Validation

<!doctype html>
<html lang="en">
<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

    <title>Hello, world!</title>
</head>
<body>
    <form class="needs-validation" novalidate>
        <div class="form-row">
            <div class="col-md-4 mb-3">
                <label for="validationCustom01">First name</label>
                <input type="text" class="form-control" id="validationCustom01" placeholder="First name" value="Mark" required>
                <div class="valid-feedback">
                    Looks good!
                </div>
            </div>
            <div class="col-md-4 mb-3">
                <label for="validationCustom02">Last name</label>
                <input type="text" class="form-control" id="validationCustom02" placeholder="Last name" value="Otto" required>
                <div class="valid-feedback">
                    Looks good!
                </div>
            </div>
            <div class="col-md-4 mb-3">
                <label for="validationCustomUsername">Username</label>
                <div class="input-group">
                    <div class="input-group-prepend">
                        <span class="input-group-text" id="inputGroupPrepend">@</span>
                    </div>
                    <input type="text" class="form-control" id="validationCustomUsername" placeholder="Username" aria-describedby="inputGroupPrepend" required>
                    <div class="invalid-feedback">
                        Please choose a username.
                    </div>
                </div>
            </div>
        </div>
        <div class="form-row">
            <div class="col-md-6 mb-3">
                <label for="validationCustom03">City</label>
                <input type="text" class="form-control" id="validationCustom03" placeholder="City" required>
                <div class="invalid-feedback">
                    Please provide a valid city.
                </div>
            </div>
            <div class="col-md-3 mb-3">
                <label for="validationCustom04">State</label>
                <input type="text" class="form-control" id="validationCustom04" placeholder="State" required>
                <div class="invalid-feedback">
                    Please provide a valid state.
                </div>
            </div>
            <div class="col-md-3 mb-3">
                <label for="validationCustom05">Zip</label>
                <input type="text" class="form-control" id="validationCustom05" placeholder="Zip" required>
                <div class="invalid-feedback">
                    Please provide a valid zip.
                </div>
            </div>
        </div>
        <div class="form-group">
            <div class="form-check">
                <input class="form-check-input" type="checkbox" value="" id="invalidCheck" required>
                <label class="form-check-label" for="invalidCheck">
                    Agree to terms and conditions
                </label>
                <div class="invalid-feedback">
                    You must agree before submitting.
                </div>
            </div>
        </div>
        <button class="btn btn-primary" type="submit">Submit form</button>
    </form>

    <script>
        // Example starter JavaScript for disabling form submissions if there are invalid fields
        (function () {
            'use strict';
            window.addEventListener('load', function () {
                // Fetch all the forms we want to apply custom Bootstrap validation styles to
                var forms = document.getElementsByClassName('needs-validation');
                // Loop over them and prevent submission
                var validation = Array.prototype.filter.call(forms, function (form) {
                    form.addEventListener('submit', function (event) {
                        if (form.checkValidity() === false) {
                            event.preventDefault();
                            event.stopPropagation();
                        }
                        form.classList.add('was-validated');
                    }, false);
                });
            }, false);
        })();
    </script>

    <!-- Optional JavaScript -->
    <!-- jQuery first, then Popper.js, then Bootstrap JS -->
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
</body>
</html>

畫面為

欄位的 :invalid and :valid 樣式是用 .was-validated class 來呈現。