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HTML

About HTML Preprocessors

HTML preprocessors can make writing HTML more powerful or convenient. For instance, Markdown is designed to be easier to write and read for text documents and you could write a loop in Pug.

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Adding Classes

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. So you don't have access to higher-up elements like the <html> tag. If you want to add classes there that can affect the whole document, this is the place to do it.

About the <head>

In CodePen, whatever you write in the HTML editor is what goes within the <body> tags in a basic HTML5 template. If you need things in the <head> of the document, put that code here.

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Insecure Resource

The resource you are linking to is using the 'http' protocol, which may not work when the browser is using https.

CSS

About CSS Preprocessors

CSS preprocessors help make authoring CSS easier. All of them offer things like variables and mixins to provide convenient abstractions.

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CSS Base

About CSS Base

It's a common practice to apply CSS to a page that styles elements such that they are consistent across all browsers. We offer two of the most popular choices: normalize.css and a reset. Or, choose Neither and nothing will be applied.

Vendor Prefixing

About Vendor Prefixing

To get the best cross-browser support, it is a common practice to apply vendor prefixes to CSS properties and values that require them to work. For instance -webkit- or -moz-.

We offer two popular choices: Autoprefixer (which processes your CSS server-side) and -prefix-free (which applies prefixes via a script, client-side).

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JavaScript

About JavaScript Preprocessors

JavaScript preprocessors can help make authoring JavaScript easier and more convenient.

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Babel includes JSX processing.

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Packages

Add Packages

Search for and use JavaScript packages from npm here. By selecting a package, an import statement will be added to the top of the JavaScript editor for this package.

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Using packages here is powered by esm.sh, which makes packages from npm not only available on a CDN, but prepares them for native JavaScript ESM usage.

All packages are different, so refer to their docs for how they work.

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HTML 

              
                <h2>整页选项卡</h2>
<p>单击链接以显示“当前”页面：</p>
<button class="tablink" onclick="openPage('Home', this, 'red')">Home</button>
<button class="tablink" onclick="openPage('News', this, 'green')" id="defaultOpen">News</button>
<button class="tablink" onclick="openPage('Contact', this, 'blue')">Contact</button>
<button class="tablink" onclick="openPage('About', this, 'orange')">About</button>

<div id="Home" class="tabcontent">
  <h3>Home</h3>
  <p>Home is where the heart is..</p>
</div>

<div id="News" class="tabcontent">
  <h3>News</h3>
  <p>Some news this fine day!</p>
</div>

<div id="Contact" class="tabcontent">
  <h3>Contact</h3>
  <p>Get in touch, or swing by for a cup of coffee.</p>
</div>

<div id="About" class="tabcontent">
  <h3>About</h3>
  <p>Who we are and what we do.</p>
</div>
!

CSS 

              
                /* 将正文和文档的高度设置为100%，以启用“整页选项卡” */
body, html {
  height: 100%;
  margin: 0;
  font-family: Arial;
}

/* 样式选项卡链接 */
.tablink {
  background-color: #555;
  color: white;
  float: left;
  border: none;
  outline: none;
  cursor: pointer;
  padding: 14px 16px;
  font-size: 17px;
  width: 25%;
}

.tablink:hover {
  background-color: #777;
}

/* 设置选项卡内容的样式（并添加高度：全页内容为100%） */
.tabcontent {
  color: white;
  display: none;
  padding: 100px 20px;
  height: 100%;
}

#Home {background-color: red;}
#News {background-color: green;}
#Contact {background-color: blue;}
#About {background-color: orange;}
!

JS 

              
                function openPage(pageName, elmnt, color) {
  // 默认情况下，使用class=“tabcontent”隐藏所有元素
  var i, tabcontent, tablinks;
  tabcontent = document.getElementsByClassName("tabcontent");
  for (i = 0; i < tabcontent.length; i++) {
    tabcontent[i].style.display = "none";
  }

  // 删除所有标签链接/按钮的背景色
  tablinks = document.getElementsByClassName("tablink");
  for (i = 0; i < tablinks.length; i++) {
    tablinks[i].style.backgroundColor = "";
  }

  // 显示特定选项卡内容
  document.getElementById(pageName).style.display = "block";

  // 将特定颜色添加到用于打开选项卡内容的按钮
  elmnt.style.backgroundColor = color;
}

// 获取id为=“defaultOpen”的元素并单击它
document.getElementById("defaultOpen").click();
!
999px

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