这可能是一个微不足道的问题，但我想知道如何在页面加载时打开特定选项卡。在下面，只有选项卡菜单，并在单击其中一个选项卡后加载内容。而不是那样，我可以使用标签菜单和＆＃34;伦敦＆＃34;加载并在页面加载时可见？
function openCity(evt, cityName) {
// Declare all variables
var i, tabcontent, tablinks;
// Get all elements with class="tabcontent" and hide them
tabcontent = document.getElementsByClassName("tabcontent");
for (i = 0; i < tabcontent.length; i++) {
tabcontent[i].style.display = "none";
}
// Get all elements with class="tablinks" and remove the class "active"
tablinks = document.getElementsByClassName("tablinks");
for (i = 0; i < tablinks.length; i++) {
tablinks[i].className = tablinks[i].className.replace(" active", "");
}
// Show the current tab, and add an "active" class to the link that opened the tab
document.getElementById(cityName).style.display = "block";
evt.currentTarget.className += " active";
} /* Style the list */
ul.tab {
list-style-type: none;
margin: 0;
padding: 0;
overflow: hidden;
border: 1px solid #ccc;
background-color: #f1f1f1;
}
/* Float the list items side by side */
ul.tab li {float: left;}
/* Style the links inside the list items */
ul.tab li a {
display: inline-block;
color: black;
text-align: center;
padding: 14px 16px;
text-decoration: none;
transition: 0.3s;
font-size: 17px;
}
/* Change background color of links on hover */
ul.tab li a:hover {background-color: #ddd;}
/* Create an active/current tablink class */
ul.tab li a:focus, .active {background-color: #ccc;}
/* Style the tab content */
.tabcontent {
display: none;
padding: 6px 12px;
border: 1px solid #ccc;
border-top: none;
} <ul class="tab">
<li><a href="#" class="tablinks" onclick="openCity(event, 'London')">London</a></li>
<li><a href="#" class="tablinks" onclick="openCity(event, 'Paris')">Paris</a></li>
<li><a href="#" class="tablinks" onclick="openCity(event, 'Tokyo')">Tokyo</a></li>
</ul>
<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>
答案 0 :(得分：1)
您可以在css中定义tabcontent首先display block，就像这样
.tabcontent:nth-of-type(1){display:block;}
function openCity(evt, cityName) {
// Declare all variables
var i, tabcontent, tablinks;
// Get all elements with class="tabcontent" and hide them
tabcontent = document.getElementsByClassName("tabcontent");
for (i = 0; i < tabcontent.length; i++) {
tabcontent[i].style.display = "none";
}
// Get all elements with class="tablinks" and remove the class "active"
tablinks = document.getElementsByClassName("tablinks");
for (i = 0; i < tablinks.length; i++) {
tablinks[i].className = tablinks[i].className.replace(" active", "");
}
// Show the current tab, and add an "active" class to the link that opened the tab
document.getElementById(cityName).style.display = "block";
evt.currentTarget.className += " active";
} /* Style the list */
ul.tab {
list-style-type: none;
margin: 0;
padding: 0;
overflow: hidden;
border: 1px solid #ccc;
background-color: #f1f1f1;
}
/* Float the list items side by side */
ul.tab li {float: left;}
/* Style the links inside the list items */
ul.tab li a {
display: inline-block;
color: black;
text-align: center;
padding: 14px 16px;
text-decoration: none;
transition: 0.3s;
font-size: 17px;
}
/* Change background color of links on hover */
ul.tab li a:hover {background-color: #ddd;}
/* Create an active/current tablink class */
ul.tab li a:focus, .active {background-color: #ccc;}
/* Style the tab content */
.tabcontent {
display: none;
padding: 6px 12px;
border: 1px solid #ccc;
border-top: none;
}
.tabcontent:nth-of-type(1){display:block;} <ul class="tab">
<li><a href="#" class="tablinks" onclick="openCity(event, 'London')">London</a></li>
<li><a href="#" class="tablinks" onclick="openCity(event, 'Paris')">Paris</a></li>
<li><a href="#" class="tablinks" onclick="openCity(event, 'Tokyo')">Tokyo</a></li>
</ul>
<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>
============第二个选项是你可以默认显示html显示为一个
function openCity(evt, cityName) {
// Declare all variables
var i, tabcontent, tablinks;
// Get all elements with class="tabcontent" and hide them
tabcontent = document.getElementsByClassName("tabcontent");
for (i = 0; i < tabcontent.length; i++) {
tabcontent[i].style.display = "none";
}
// Get all elements with class="tablinks" and remove the class "active"
tablinks = document.getElementsByClassName("tablinks");
for (i = 0; i < tablinks.length; i++) {
tablinks[i].className = tablinks[i].className.replace(" active", "");
}
// Show the current tab, and add an "active" class to the link that opened the tab
document.getElementById(cityName).style.display = "block";
evt.currentTarget.className += " active";
} /* Style the list */
ul.tab {
list-style-type: none;
margin: 0;
padding: 0;
overflow: hidden;
border: 1px solid #ccc;
background-color: #f1f1f1;
}
/* Float the list items side by side */
ul.tab li {float: left;}
/* Style the links inside the list items */
ul.tab li a {
display: inline-block;
color: black;
text-align: center;
padding: 14px 16px;
text-decoration: none;
transition: 0.3s;
font-size: 17px;
}
/* Change background color of links on hover */
ul.tab li a:hover {background-color: #ddd;}
/* Create an active/current tablink class */
ul.tab li a:focus, .active {background-color: #ccc;}
/* Style the tab content */
.tabcontent {
display: none;
padding: 6px 12px;
border: 1px solid #ccc;
border-top: none;
} <ul class="tab">
<li><a href="#" class="tablinks active" onclick="openCity(event, 'London')">London</a></li>
<li><a href="#" class="tablinks" onclick="openCity(event, 'Paris')">Paris</a></li>
<li><a href="#" class="tablinks" onclick="openCity(event, 'Tokyo')">Tokyo</a></li>
</ul>
<div id="London" class="tabcontent" style=display:block;>
<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>
答案 1 :(得分：1)
一种解决方案可以是模拟点击。
添加：
explicit
document.getElementsByClassName("tablinks")[0].click();
function openCity(evt, cityName) {
// Declare all variables
var i, tabcontent, tablinks;
// Get all elements with class="tabcontent" and hide them
tabcontent = document.getElementsByClassName("tabcontent");
for (i = 0; i < tabcontent.length; i++) {
tabcontent[i].style.display = "none";
}
// Get all elements with class="tablinks" and remove the class "active"
tablinks = document.getElementsByClassName("tablinks");
for (i = 0; i < tablinks.length; i++) {
tablinks[i].className = tablinks[i].className.replace(" active", "");
}
// Show the current tab, and add an "active" class to the link that opened the tab
document.getElementById(cityName).style.display = "block";
evt.currentTarget.className += " active";
}
document.getElementsByClassName("tablinks")[0].click();/* Style the list */
ul.tab {
list-style-type: none;
margin: 0;
padding: 0;
overflow: hidden;
border: 1px solid #ccc;
background-color: #f1f1f1;
}
/* Float the list items side by side */
ul.tab li {float: left;}
/* Style the links inside the list items */
ul.tab li a {
display: inline-block;
color: black;
text-align: center;
padding: 14px 16px;
text-decoration: none;
transition: 0.3s;
font-size: 17px;
}
/* Change background color of links on hover */
ul.tab li a:hover {background-color: #ddd;}
/* Create an active/current tablink class */
ul.tab li a:focus, .active {background-color: #ccc;}
/* Style the tab content */
.tabcontent {
display: none;
padding: 6px 12px;
border: 1px solid #ccc;
border-top: none;
}
答案 2 :(得分：0)
尝试
.tabcontent:first-child{
display:block;
}