默认加载标签内容

Question

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的选项卡。在下文中，只有选项卡菜单存在，并且在点击任一选项卡后加载内容。取而代之的是，例如，我可以在页面加载时加载和显示“标签”菜单和“伦敦”的内容吗？

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>

Answer 1

你可以在CSS中做到这一点定义tabcontent第一display block因为这样

.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，你可以在HTML默认显示deinfe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>

Answer 2

一种解决方案可以是模拟点击。

补充一点：

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; 
 
}

<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>

Answer 3

尝试

.tabcontent:first-child{ 
    display:block; 
}