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HTML

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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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About the <head>

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Insecure Resource

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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.

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HTML 

              
                <div class="topics_box">
  <!-- もしリンクあり見出しがあるなら<div class="topics_link">アンカーリンク</div>が出る -->
  <div class="topics_single_list">
    <!-- ここにアンカーリンクが生成される -->
  </div>
</div>
<h2 class="topics_content">
  <h２ class="ttl_link">見出し1</h2>
  <div class="topics_txt">
    本文
  </div>
  <h2 class="ttl_link">見出し2</h2>
  <div class="topics_txt">
    本文
  </div>
    <h2 class="ttl_link">見出し3</h2>
  <div class="topics_txt">
    本文
  </div>
</div>
!

CSS 

              
                .topics_link{
  font-size:20px;
}
.topics_content{
  margin-top:20px;
}
.ttl_link{
  font-size:20px;
  margin-bottom:10px;
}
.topics_txt{
  height:200px;
}
!

JS 

              
                $(function(){

var wrapper_single = $('.wrapper_single');

//空の配列を作る
var ttl_name = [];
var ttl_link = [];

//見出しがあるなら下記追加
if($('.ttl_link').length){
  $('.topics_box').prepend('<div class="topics_link">アンカーリンク</div>');
}else{
}

//eachでttl_linkをそれぞれ見る
$('.ttl_link').each(function(i){
  //見出しにidを連番を振る
   $(this).attr('id','link_' + (i+1));
   //ttl_nameにタイトルを格納
   var name =$(this).text();
   ttl_name.push(name);

   //ttl_linkにidを格納
   var link =$(this).attr('id');
   ttl_link.push(link);

   var single_list =$('.topics_single_list');
   single_list.append('<div><a href="#'+ttl_link[i]+'">'+ttl_name[i]+'</a></div>');
});
});
!
999px

Console