javascript - 如何使用 HTML、CSS 和 JavaScript 让多个选项卡式部分在加载时打开第一个选项卡？

Question

我已将多个选项卡式部分添加到我的网页，但我无法确保第二个选项卡式部分在加载时也打开第一个选项卡。我目前正在关注 this来自 W3Schools 的教程，这是我目前在 W3Schools 上的代码:

body {font-family: Arial;}

/* Style the tab */
.tab {
  overflow: hidden;
  border: 1px solid #ccc;
  background-color: #f1f1f1;
}

/* Style the buttons inside the tab */
.tab button {
  background-color: inherit;
  float: left;
  border: none;
  outline: none;
  cursor: pointer;
  padding: 14px 16px;
  transition: 0.3s;
  font-size: 17px;
}

/* Change background color of buttons on hover */
.tab button:hover {
  background-color: #ddd;
}

/* Create an active/current tablink class */
.tab button.active {
  background-color: #ccc;
}

/* Style the tab content */
.tabcontent {
  display: none;
  padding: 6px 12px;
  border: 1px solid #ccc;
  border-top: none;
}

<p>In this example, we use JavaScript to "click" on the London button, to open the tab on page load.</p>

<!--first tab-->

<div class="tab">
  <button class="tablinks" onclick="openCity(event, 'London')" id="defaultOpen">London</button>
  <button class="tablinks" onclick="openCity(event, 'Paris')">Paris</button>
  <button class="tablinks" onclick="openCity(event, 'Tokyo')">Tokyo</button>
</div>

<div id="London" class="tabcontent">
  <h3>London</h3>
  <p>London is the capital city of England.</p>
</div>

<div id="Paris" class="tabcontent">
  <h3>Paris</h3>
  <p>Paris is the capital of France.</p> 
</div>

<div id="Tokyo" class="tabcontent">
  <h3>Tokyo</h3>
  <p>Tokyo is the capital of Japan.</p>
</div>

<br><br><br><br><br>

<!--second tab-->

<div class="tab">
  <button class="tablinks" onclick="openCity(event, '1')" id="defaultOpen">London</button>
  <button class="tablinks" onclick="openCity(event, '2')">Paris</button>
  <button class="tablinks" onclick="openCity(event, '3')">Tokyo</button>
</div>

<div id="1" class="tabcontent">
  <h3>Tokyo</h3>
  <p>Tokyo is the capital of Japan.</p>
</div>

<script>
function openCity(evt, cityName) {
  var i, tabcontent, tablinks;
  tabcontent = document.getElementsByClassName("tabcontent");
  for (i = 0; i < tabcontent.length; i++) {
    tabcontent[i].style.display = "none";
  }
  tablinks = document.getElementsByClassName("tablinks");
  for (i = 0; i < tablinks.length; i++) {
    tablinks[i].className = tablinks[i].className.replace(" active", "");
  }
  document.getElementById(cityName).style.display = "block";
  evt.currentTarget.className += " active";
}

// Get the element with id="defaultOpen" and click on it
document.getElementById("defaultOpen").click();
</script>

我已经设法在第一个选项卡下方创建了第二个选项卡部分，但我无法让两个选项卡部分同时在页面加载时显示第一个选项卡。

Answer 1

对城市使用类名而不是 ID。向事件内容添加“显示”类名:

function openCity(evt, cityName) {
  var i, tabcontent, tablinks;
  tabcontent = document.getElementsByClassName("tabcontent");
  for (var i = 0; i < tabcontent.length; i++) {
    tabcontent[i].classList.remove('show');
  }
  tablinks = document.getElementsByClassName("tablinks");
  for (var i = 0; i < tablinks.length; i++) {
    tablinks[i].classList.remove('active');
  }
  document.getElementsByClassName(cityName)[0].classList.add('show');
  document.getElementsByClassName(cityName)[1].classList.add('show');
  var cuttentTabClass = evt.currentTarget.className.split(" ")[1];
  console.log(cuttentTabClass);
  document.getElementsByClassName(cuttentTabClass)[0].classList.add('active');
  document.getElementsByClassName(cuttentTabClass)[1].classList.add('active');
}

// Get the element with id="defaultOpen" and click on it
document.getElementById("defaultOpen").click();

.tab {
  overflow: hidden;
  border: 1px solid #ccc;
  background-color: #f1f1f1;
}

/* Style the buttons inside the tab */
.tab button {
  background-color: inherit;
  float: left;
  border: none;
  outline: none;
  cursor: pointer;
  padding: 14px 16px;
  transition: 0.3s;
  font-size: 17px;
}

/* Change background color of buttons on hover */
.tab button:hover {
  background-color: #ddd;
}

/* Create an active/current tablink class */
.tab button.active {
  background-color: #ccc;
}

/* Style the tab content */
.tabcontent {
  display: none;
  padding: 6px 12px;
  border: 1px solid #ccc;
  border-top: none;
}
.tabcontent.show {
	display: block;
}

<p>In this example, we use JavaScript to "click" on the London button, to open the tab on page load.</p>

<!--first tab-->

<div class="tab">
  <button class="tablinks l" onclick="openCity(event, 'london')" id="defaultOpen">London</button>
  <button class="tablinks p" onclick="openCity(event, 'paris')">Paris</button>
  <button class="tablinks t" onclick="openCity(event, 'tokyo')">Tokyo</button>
</div>

<div class="tabcontent london">
  <h3>London</h3>
  <p>London is the capital city of England.</p>
</div>

<div class="tabcontent paris">
  <h3>Paris</h3>
  <p>Paris is the capital of France.</p> 
</div>

<div class="tabcontent tokyo">
  <h3>Tokyo</h3>
  <p>Tokyo is the capital of Japan.</p>
</div>

<br><br><br><br><br>

<!--second tab-->

<div class="tab">
  <button class="tablinks l" onclick="openCity(event, 'london')">London</button>
  <button class="tablinks p" onclick="openCity(event, 'paris')">Paris</button>
  <button class="tablinks t" onclick="openCity(event, 'tokyo')">Tokyo</button>
</div>

<div class="tabcontent london">
  <h3>London</h3>
  <p>London is the capital city of England.</p>
</div>

<div class="tabcontent paris">
  <h3>Paris</h3>
  <p>Paris is the capital of France.</p> 
</div>

<div class="tabcontent tokyo">
  <h3>Tokyo</h3>
  <p>Tokyo is the capital of Japan.</p>
</div>