我有两个从导航栏打开的模式。设置模式工作得很好，另一个从“ +”符号（＃quick-add-task-modal）打开的模式只会使屏幕褪色，而不会显示。我看过一百万遍代码，看不到它们之间有什么区别。似乎是相同的机制，我从Bootstrap 4文档中复制了它，只更改了内容。
<!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/4.3.1/css/bootstrap.min.css"
integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<link rel="stylesheet" href="styles/styles.css">
</head>
<body>
<!-- Navbar -->
<nav class="navbar navbar-expand-sm navbar-dark bg-dark">
<div class="col-3">
</div>
<img src="images/tomato.png" alt="Tomato icon" id="tomatoIcon">
<a class="navbar-brand" href="#">Koroko</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarToggler"
aria-controls="navbarToggler" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarToggler">
<ul class="navbar-nav ml-auto">
<li class="nav-item mx-2">
<a class="nav-link" data-toggle="modal" data-target="#quick-add-task-modal">+</a>
</li>
<li class="nav-item mx-2">
<a class="nav-link align-top" data-toggle="modal" data-target="#settingsModal">Settings</a>
</li>
<li class="nav-item mx-2">
<a class="nav-link" href="#">About</a>
</li>
</ul>
</div>
<div class="col-3">
</div>
</nav>
<div class="container">
<div class="row mt-5">
<div class="col-sm-4" id="inbox">
<i class="fas fa-inbox mx-2"></i>
<span id="inbox-text">Inbox</span>
<span id="inbox-number-of-items"</span>
</div>
<div class="col-sm-8">
div id content placeholder
</div>
</div>
<div class="row mt-3">
<div class="col sm-4">
<i class="fas fa-calendar-alt mx-2"></i>
<span>Today</span>
</div>
<div class="col-sm-8">
div id content placeholder
</div>
</div>
</div>
<div class="mainDiv d-flex lemonChiffon flex-column">
<div class="container-fluid" id="timer">
<div class="justify-content-center text-center">
<div class="col-12">
<button type="button" class="btn btn-success" id="timerButton">
<span id="minutes">25</span>
<span id="colon">:</span>
<span id="seconds">00</span>
<i class="fa fa-play" aria-hidden="false" id="fa-play"> </i>
<i class="fa fa-pause" aria-hidden="false" id="fa-pause"> </i>
</button>
</div>
</div>
<div class="justify-content-center text-center">
<div class="col-12">
<span id="nextBreak">Next break is a <span class="bold">short break</span></span>
</div>
</div>
</div>
</div>
<!-- Settings Modal -->
<div class="modal fade" id="settingsModal" tabindex="-1" role="dialog" aria-labelledby="settingsModal"
aria-hidden="true">
<div class="modal-dialog modal-dialog-centered" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="settingsModal">Settings</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="modal-body">
<div class="container-fluid">
<div class="d-flex flex-column p-2">
<div class="form-check">
<input class="form-check-input" type="checkbox" value="" id="alertsCheckbox">
<label class="form-check-label" for="alertsCheckbox">
Enable browser alerts
</label>
</div> <!-- INLINE STYLING. NOT RECOMMENDED. LOOK FOR ALTERNATIVES. -->
<div style="font-size: 0.8em;" class="pl-4 mb-3">Display browser alert when pomodoro/break
is over</div>
<div class="form-check">
<input class="form-check-input" type="checkbox" value="" id="disableSoundCheckbox">
<label class="form-check-label" for="disableSoundCheckbox">
Disable sound
</label>
</div>
<div class="mt-3 font-weight-bold mx-auto">Set custom times<span class="font-weight-normal">
(in minutes) </span>
</div>
</div>
<form>
<div class="form-row">
<div class="form-group col-md-4">
<label for="inputPomodoro">Pomodoro</label>
<input type="number" min="1" max="90" class="form-control" id="inputPomodoro"
placeholder="25">
</div>
<div class="form-group col-md-4">
<label for="inputShortBreak">Short break</label>
<input type="number" min="1" max="90" class="form-control" id="inputShortBreak"
placeholder="5">
</div>
<div class="form-group col-md-4">
<label for="inputLongBreak">Long break</label>
<input type="number" min="1" max="90" class="form-control" id="inputLongBreak"
placeholder="15">
</div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal"
id="closeModal">Save</button>
<button type="button" class="btn btn-primary" id="resetButton">Reset to default</button>
</div>
</div>
</div>
</div>
</div>
<!-- Quick Add Task Modal -->
<div class="modal fade" id="quick-add-task-modal" tabindex="-1" role="dialog" aria-labelledby="quick-add-task-modal"
aria-hidden="true">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="quick-add-task-modal">Quick add task</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="modal-body">
MODAL BODY GOES HERE
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
<button type="button" class="btn btn-primary">Save changes</button>
</div>
</div>
</div>
</div>
<script defer src="https://use.fontawesome.com/releases/v5.0.0/js/all.js"></script>
<--Bootstrap stuff -->
<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/1.14.7/umd/popper.min.js"
integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1"
crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"
integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM"
crossorigin="anonymous"></script>
<script src="https://cdn.rawgit.com/alertifyjs/alertify.js/v1.0.10/dist/js/alertify.js"></script>
<script src="./scripts/bundle.js"></script>
</body>
</html>
答案 0 :(得分：1)
一个愚蠢的错误，您错过了一个关闭div标签。在</div>
<!-- Quick Add Task Modal -->
此处更新了代码。
<!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/4.3.1/css/bootstrap.min.css"
integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<link rel="stylesheet" href="styles/styles.css">
</head>
<body>
<!-- Navbar -->
<nav class="navbar navbar-expand-sm navbar-dark bg-dark">
<div class="col-3">
</div>
<img src="images/tomato.png" alt="Tomato icon" id="tomatoIcon">
<a class="navbar-brand" href="#">Koroko</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarToggler"
aria-controls="navbarToggler" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarToggler">
<ul class="navbar-nav ml-auto">
<li class="nav-item mx-2">
<a class="nav-link" data-toggle="modal" data-target="#quick-add-task-modal">+</a>
</li>
<li class="nav-item mx-2">
<a class="nav-link align-top" data-toggle="modal" data-target="#settingsModal">Settings</a>
</li>
<li class="nav-item mx-2">
<a class="nav-link" href="#">About</a>
</li>
</ul>
</div>
<div class="col-3">
</div>
</nav>
<div class="container">
<div class="row mt-5">
<div class="col-sm-4" id="inbox">
<i class="fas fa-inbox mx-2"></i>
<span id="inbox-text">Inbox</span>
<span id="inbox-number-of-items"</span>
</div>
<div class="col-sm-8">
div id content placeholder
</div>
</div>
<div class="row mt-3">
<div class="col sm-4">
<i class="fas fa-calendar-alt mx-2"></i>
<span>Today</span>
</div>
<div class="col-sm-8">
div id content placeholder
</div>
</div>
</div>
<div class="mainDiv d-flex lemonChiffon flex-column">
<div class="container-fluid" id="timer">
<div class="justify-content-center text-center">
<div class="col-12">
<button type="button" class="btn btn-success" id="timerButton">
<span id="minutes">25</span>
<span id="colon">:</span>
<span id="seconds">00</span>
<i class="fa fa-play" aria-hidden="false" id="fa-play"> </i>
<i class="fa fa-pause" aria-hidden="false" id="fa-pause"> </i>
</button>
</div>
</div>
<div class="justify-content-center text-center">
<div class="col-12">
<span id="nextBreak">Next break is a <span class="bold">short break</span></span>
</div>
</div>
</div>
</div>
<!-- Settings Modal -->
<div class="modal fade" id="settingsModal" tabindex="-1" role="dialog" aria-labelledby="settingsModal"
aria-hidden="true">
<div class="modal-dialog modal-dialog-centered" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="settingsModal">Settings</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="modal-body">
<div class="container-fluid">
<div class="d-flex flex-column p-2">
<div class="form-check">
<input class="form-check-input" type="checkbox" value="" id="alertsCheckbox">
<label class="form-check-label" for="alertsCheckbox">
Enable browser alerts
</label>
</div> <!-- INLINE STYLING. NOT RECOMMENDED. LOOK FOR ALTERNATIVES. -->
<div style="font-size: 0.8em;" class="pl-4 mb-3">Display browser alert when pomodoro/break
is over</div>
<div class="form-check">
<input class="form-check-input" type="checkbox" value="" id="disableSoundCheckbox">
<label class="form-check-label" for="disableSoundCheckbox">
Disable sound
</label>
</div>
<div class="mt-3 font-weight-bold mx-auto">Set custom times<span class="font-weight-normal">
(in minutes) </span>
</div>
</div>
<form>
<div class="form-row">
<div class="form-group col-md-4">
<label for="inputPomodoro">Pomodoro</label>
<input type="number" min="1" max="90" class="form-control" id="inputPomodoro"
placeholder="25">
</div>
<div class="form-group col-md-4">
<label for="inputShortBreak">Short break</label>
<input type="number" min="1" max="90" class="form-control" id="inputShortBreak"
placeholder="5">
</div>
<div class="form-group col-md-4">
<label for="inputLongBreak">Long break</label>
<input type="number" min="1" max="90" class="form-control" id="inputLongBreak"
placeholder="15">
</div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal"
id="closeModal">Save</button>
<button type="button" class="btn btn-primary" id="resetButton">Reset to default</button>
</div>
</div>
</div>
</div>
</div>
</div>
<!-- Quick Add Task Modal -->
<div class="modal fade" id="quick-add-task-modal" tabindex="-1" role="dialog" aria-labelledby="quick-add-task-modal"
aria-hidden="true">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="quick-add-task-modal">Quick add task</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="modal-body">
MODAL BODY GOES HERE
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
<button type="button" class="btn btn-primary">Save changes</button>
</div>
</div>
</div>
</div>
<script defer src="https://use.fontawesome.com/releases/v5.0.0/js/all.js"></script>
<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/1.14.7/umd/popper.min.js"
integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1"
crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"
integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM"
crossorigin="anonymous"></script>
<script src="https://cdn.rawgit.com/alertifyjs/alertify.js/v1.0.10/dist/js/alertify.js"></script>
<script src="./scripts/bundle.js"></script>
</body>
</html>