{"id":9357,"date":"2025-11-18T12:22:14","date_gmt":"2025-11-18T03:22:14","guid":{"rendered":"https:\/\/fastcoding.jp\/blog\/?p=9357"},"modified":"2025-11-18T12:22:21","modified_gmt":"2025-11-18T03:22:21","slug":"reading-progress-dots","status":"publish","type":"post","link":"https:\/\/fastcoding.jp\/blog\/all\/ui-ux\/reading-progress-dots\/","title":{"rendered":"\u300c\u8aad\u307f\u304a\u308f\u3063\u305f\u8a3c\u62e0\u3092\u898b\u305b\u308b\u300d\u2500 \u9032\u6357\u3092&#8221;\u70b9&#8221;\u3067\u8868\u3057\u3066\u8aad\u4e86\u7387\u3092\u4e0a\u3052\u308b"},"content":{"rendered":"<div class=\"the_content\">\n<p>\u3053\u3093\u306b\u3061\u306f\u3001Web\u30c7\u30a3\u30ec\u30af\u30bf\u30fc\u306e BigVi\u3067\u3059\u3002<\/p>\n\n\n\n<p>\u6700\u8fd1\u3001\u79c1\u304c\u5bfe\u5fdc\u3057\u305f\u30d6\u30ed\u30b0\u30b5\u30a4\u30c8\u306e\u30ea\u30cb\u30e5\u30fc\u30a2\u30eb\u3067\u300c\u8aad\u4e86\u7387\u304c\u4f4e\u3044\u300d\u3068\u3044\u3046\u554f\u984c\u304c\u3042\u308a\u307e\u3057\u305f\u3002\u8a18\u4e8b\u306f\u9577\u3044\u3067\u3059\u304c\u3001\u9014\u4e2d\u3067\u96e2\u8131\u3059\u308b\u30e6\u30fc\u30b6\u30fc\u304c\u591a\u304b\u3063\u305f\u3067\u3059\u3002\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u304b\u3089\u300c\u8aad\u8005\u304c\u6700\u5f8c\u307e\u3067\u8aad\u3093\u3067\u304f\u308c\u308b\u5de5\u592b\u3092\u3057\u305f\u3044\u300d\u3068\u3044\u3046\u76f8\u8ac7\u3092\u53d7\u3051\u307e\u3057\u305f\u3002<\/p>\n\n\n\n<p>\u3053\u306e\u8ab2\u984c\u306b\u5bfe\u3057\u3066\u3001\u79c1\u306f\u30bb\u30af\u30b7\u30e7\u30f3\u9032\u6357\u8868\u793a\u3092\u63d0\u6848\u3057\u307e\u3057\u305f\u3002\u305f\u3060\u3057\u3001\u5e38\u306b\u8868\u793a\u3055\u308c\u308b\u30d7\u30ed\u30b0\u30ec\u30b9\u30d0\u30fc\u3067\u306f\u306a\u304f\u3001\u300c\u8aad\u3093\u3060\u8a3c\u62e0\u300d\u3068\u3057\u3066\u70b9\u304c\u706f\u308b\u65b9\u5f0f\u3067\u3059\u3002\u3053\u308c\u304c\u610f\u5916\u3068\u52b9\u679c\u304c\u3042\u308a\u307e\u3057\u305f\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u306a\u305c\u5e38\u6642\u8868\u793a\u306e\u30d7\u30ed\u30b0\u30ec\u30b9\u30d0\u30fc\u3058\u3083\u306a\u3044\u306e\u304b<\/h2>\n\n\n\n<p>\u5b9f\u306f\u3001\u6700\u521d\u306f\u666e\u901a\u306e\u30d7\u30ed\u30b0\u30ec\u30b9\u30d0\u30fc\u3092\u4f5c\u308a\u307e\u3057\u305f\u3002\u3067\u3082\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u304c\u300c\u5727\u8feb\u611f\u304c\u3042\u308b\u300d\u3068\u8a00\u3044\u307e\u3057\u305f\u3002\u78ba\u304b\u306b\u3001\u5e38\u306b\u30b2\u30fc\u30b8\u304c\u898b\u3048\u308b\u3068\u300c\u307e\u3060\u3053\u3093\u306a\u306b\u6b8b\u3063\u3066\u308b\u300d\u3068\u3044\u3046\u6c17\u6301\u3061\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<p>\u305d\u3053\u3067\u8003\u3048\u65b9\u3092\u5909\u3048\u307e\u3057\u305f\u3002\u300c\u9032\u6357\u3092\u898b\u305b\u308b\u300d\u306e\u3067\u306f\u306a\u304f\u300c\u6210\u679c\u3092\u898b\u305b\u308b\u300d\u65b9\u5f0f\u3067\u3059\u3002\u7ae0\u3092\u8aad\u3080\u305f\u3073\u306b\u70b9\u304c\u706f\u308b\u3002\u3053\u308c\u306a\u3089\u300c\u3053\u3053\u307e\u3067\u8aad\u3093\u3060\u300d\u3068\u3044\u3046\u9054\u6210\u611f\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u5b9f\u88c5\u306e\u4ed5\u7d44\u307f<\/h2>\n\n\n\n<p>\u4eca\u56de\u306e\u5b9f\u88c5\u306f3\u3064\u306e\u90e8\u5206\u3067\u69cb\u6210\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>HTML\u69cb\u9020\uff08\u898b\u51fa\u3057\u3068\u30c9\u30c3\u30c8\u7fa4\uff09<\/li>\n\n\n\n<li>CSS\u30b9\u30bf\u30a4\u30eb\uff08\u30c9\u30c3\u30c8\u306e\u30c7\u30b6\u30a4\u30f3\u3068\u70b9\u706f\u30a2\u30cb\u30e1\u30fc\u30b7\u30e7\u30f3\uff09<\/li>\n\n\n\n<li>JavaScript\uff08IntersectionObserver\u3067\u7ae0\u306e\u8868\u793a\u3092\u76e3\u8996\uff09<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">HTML\u69cb\u9020<\/h3>\n\n\n\n<p>\u5404\u7ae0\u306e\u898b\u51fa\u3057\u306e\u53f3\u5074\u306b\u3001\u5c0f\u3055\u306a\u30c9\u30c3\u30c8\u7fa4\u3092\u914d\u7f6e\u3057\u307e\u3059\u3002\u30c9\u30c3\u30c8\u306e\u6570\u306f\u7ae0\u306e\u7dcf\u6570\u3068\u540c\u3058\u3067\u3059\u3002<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: xml; title: ; notranslate\" title=\"\">\n&lt;article class=&quot;blog-post&quot;&gt;\n  &lt;!-- \u7ae01 --&gt;\n  &lt;section class=&quot;chapter&quot; data-chapter=&quot;1&quot;&gt;\n    &lt;div class=&quot;chapter-header&quot;&gt;\n      &lt;h2&gt;\u306a\u305c\u5e38\u6642\u8868\u793a\u306e\u30d7\u30ed\u30b0\u30ec\u30b9\u30d0\u30fc\u3058\u3083\u306a\u3044\u306e\u304b&lt;\/h2&gt;\n      &lt;div class=&quot;progress-dots&quot;&gt;\n        &lt;span class=&quot;dot&quot; data-dot=&quot;1&quot;&gt;&lt;\/span&gt;\n        &lt;span class=&quot;dot&quot; data-dot=&quot;2&quot;&gt;&lt;\/span&gt;\n        &lt;span class=&quot;dot&quot; data-dot=&quot;3&quot;&gt;&lt;\/span&gt;\n        &lt;span class=&quot;dot&quot; data-dot=&quot;4&quot;&gt;&lt;\/span&gt;\n      &lt;\/div&gt;\n    &lt;\/div&gt;\n    &lt;p&gt;\u7ae0\u306e\u5185\u5bb9...&lt;\/p&gt;\n  &lt;\/section&gt;\n\n  &lt;!-- \u7ae02 --&gt;\n  &lt;section class=&quot;chapter&quot; data-chapter=&quot;2&quot;&gt;\n    &lt;div class=&quot;chapter-header&quot;&gt;\n      &lt;h2&gt;\u5b9f\u88c5\u306e\u4ed5\u7d44\u307f&lt;\/h2&gt;\n      &lt;div class=&quot;progress-dots&quot;&gt;\n        &lt;span class=&quot;dot&quot; data-dot=&quot;1&quot;&gt;&lt;\/span&gt;\n        &lt;span class=&quot;dot&quot; data-dot=&quot;2&quot;&gt;&lt;\/span&gt;\n        &lt;span class=&quot;dot&quot; data-dot=&quot;3&quot;&gt;&lt;\/span&gt;\n        &lt;span class=&quot;dot&quot; data-dot=&quot;4&quot;&gt;&lt;\/span&gt;\n      &lt;\/div&gt;\n    &lt;\/div&gt;\n    &lt;p&gt;\u7ae0\u306e\u5185\u5bb9...&lt;\/p&gt;\n  &lt;\/section&gt;\n\n  &lt;!-- \u4ee5\u4e0b\u540c\u69d8 --&gt;\n&lt;\/article&gt;\n<\/pre><\/div>\n\n\n<p>\u5404\u30bb\u30af\u30b7\u30e7\u30f3\u306b<code>data-chapter<\/code>\u5c5e\u6027\u3092\u4ed8\u3051\u3066\u3044\u307e\u3059\u3002\u3053\u308c\u3067\u4f55\u756a\u76ee\u306e\u7ae0\u304b\u3092\u5224\u5225\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">CSS\u30b9\u30bf\u30a4\u30eb<\/h3>\n\n\n\n<p>\u30c9\u30c3\u30c8\u306e\u30c7\u30b6\u30a4\u30f3\u3068\u70b9\u706f\u30a2\u30cb\u30e1\u30fc\u30b7\u30e7\u30f3\u3092\u5b9a\u7fa9\u3057\u307e\u3059\u3002\u70b9\u706f\u6642\u9593\u306f200ms\u3067\u3059\u3002\u3053\u308c\u304c\u3061\u3087\u3046\u3069\u3044\u3044\u901f\u3055\u3067\u3057\u305f\u3002<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: css; title: ; notranslate\" title=\"\">\n.chapter-header {\n  display: flex;\n  justify-content: space-between;\n  align-items: center;\n  margin-bottom: 1.5rem;\n}\n\n.progress-dots {\n  display: flex;\n  gap: 6px;\n  margin-left: 1rem;\n}\n\n.dot {\n  width: 8px;\n  height: 8px;\n  border-radius: 50%;\n  background-color: #e0e0e0;\n  transition: background-color 200ms ease-out;\n}\n\n.dot.active {\n  background-color: #2196F3;\n}\n<\/pre><\/div>\n\n\n<p>\u6700\u521d\u306f<code>#e0e0e0<\/code>\uff08\u30b0\u30ec\u30fc\uff09\u3067\u3001\u70b9\u706f\u3059\u308b\u3068<code>#2196F3<\/code>\uff08\u9752\uff09\u306b\u306a\u308a\u307e\u3059\u3002\u8272\u306f\u81ea\u7531\u306b\u5909\u3048\u3089\u308c\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">JavaScript\u306e\u5b9f\u88c5<\/h3>\n\n\n\n<p>IntersectionObserver API\u3092\u4f7f\u3044\u307e\u3059\u3002\u3053\u308c\u306f\u8981\u7d20\u304c\u753b\u9762\u5185\u306b\u5165\u3063\u305f\u304b\u3092\u691c\u77e5\u3059\u308bAPI\u3067\u3059\u3002\u5404\u7ae0\u304c\u753b\u9762\u5185\u306b\u5165\u3063\u305f\u3068\u304d\u306b\u3001\u5bfe\u5fdc\u3059\u308b\u30c9\u30c3\u30c8\u3092\u70b9\u706f\u3055\u305b\u307e\u3059\u3002<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: plain; title: ; notranslate\" title=\"\">\n\/\/ \u5404\u7ae0\u8981\u7d20\u3092\u53d6\u5f97\nconst chapters = document.querySelectorAll(&#039;.chapter&#039;);\n\n\/\/ IntersectionObserver \u306e\u8a2d\u5b9a\nconst options = {\n  root: null, \/\/ \u30d3\u30e5\u30fc\u30dd\u30fc\u30c8\u3092\u57fa\u6e96\n  rootMargin: &#039;-20% 0px -20% 0px&#039;, \/\/ \u4e0a\u4e0b20%\u306e\u4f4d\u7f6e\u3067\u5224\u5b9a\n  threshold: 0\n};\n\n\/\/ \u70b9\u706f\u6e08\u307f\u30c9\u30c3\u30c8\u3092\u8a18\u9332\nconst activatedDots = new Set();\n\n\/\/ Observer \u306e\u30b3\u30fc\u30eb\u30d0\u30c3\u30af\u95a2\u6570\nconst callback = (entries) =&gt; {\n  entries.forEach(entry =&gt; {\n    if (entry.isIntersecting) {\n      const chapterNum = entry.target.dataset.chapter;\n\n      \/\/ \u307e\u3060\u70b9\u706f\u3057\u3066\u3044\u306a\u3044\u30c9\u30c3\u30c8\u306e\u307f\u51e6\u7406\n      if (!activatedDots.has(chapterNum)) {\n        activatedDots.add(chapterNum);\n\n        \/\/ \u3059\u3079\u3066\u306e\u7ae0\u306e\u30c9\u30c3\u30c8\u7fa4\u304b\u3089\u8a72\u5f53\u756a\u53f7\u306e\u30c9\u30c3\u30c8\u3092\u70b9\u706f\n        const allDots = document.querySelectorAll(`.dot&#x5B;data-dot=&quot;${chapterNum}&quot;]`);\n        allDots.forEach(dot =&gt; {\n          dot.classList.add(&#039;active&#039;);\n        });\n      }\n    }\n  });\n};\n\n\/\/ Observer \u3092\u4f5c\u6210\u3057\u3066\u5404\u7ae0\u3092\u76e3\u8996\nconst observer = new IntersectionObserver(callback, options);\nchapters.forEach(chapter =&gt; observer.observe(chapter));\n<\/pre><\/div>\n\n\n<p>\u30dd\u30a4\u30f3\u30c8\u306f<code>rootMargin: '-20% 0px -20% 0px'<\/code>\u3067\u3059\u3002\u3053\u308c\u3067\u7ae0\u304c\u753b\u9762\u306e\u4e2d\u592e\u4ed8\u8fd1\u306b\u6765\u305f\u3068\u304d\u306b\u70b9\u706f\u3057\u307e\u3059\u3002\u4e0a\u4e0b20%\u3092\u30de\u30fc\u30b8\u30f3\u306b\u3059\u308b\u3053\u3068\u3067\u3001\u30b9\u30af\u30ed\u30fc\u30eb\u4e2d\u306b\u3061\u3087\u3046\u3069\u3044\u3044\u30bf\u30a4\u30df\u30f3\u30b0\u3067\u706f\u308a\u307e\u3059\u3002<\/p>\n\n\n\n<div class=\"wp-block-cp-codepen-gutenberg-embed-block cp_embed_wrapper\"><iframe id=\"cp_embed_ByKQymj\" src=\"\/\/codepen.io\/anon\/embed\/ByKQymj?height=450&amp;theme-id=1&amp;slug-hash=ByKQymj&amp;default-tab=result\" height=\"450\" scrolling=\"no\" frameborder=\"0\" allowfullscreen allowpaymentrequest name=\"CodePen Embed ByKQymj\" title=\"CodePen Embed ByKQymj\" class=\"cp_embed_iframe\" style=\"width:100%;overflow:hidden\">CodePen Embed Fallback<\/iframe><\/div>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e00\u5ea6\u70b9\u706f\u3057\u305f\u3089\u6d88\u3048\u306a\u3044\u4ed5\u7d44\u307f<\/h3>\n\n\n\n<p><code>activatedDots<\/code>\u3068\u3044\u3046Set\u3067\u3001\u3059\u3067\u306b\u70b9\u706f\u3057\u305f\u30c9\u30c3\u30c8\u756a\u53f7\u3092\u8a18\u9332\u3057\u3066\u3044\u307e\u3059\u3002\u3053\u308c\u3067\u4e0a\u306b\u30b9\u30af\u30ed\u30fc\u30eb\u3057\u3066\u623b\u3063\u3066\u3082\u3001\u30c9\u30c3\u30c8\u306f\u6d88\u3048\u307e\u305b\u3093\u3002\u300c\u8aad\u3093\u3060\u8a3c\u62e0\u300d\u3068\u3057\u3066\u6b8b\u308a\u7d9a\u3051\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u5b9f\u969b\u306e\u7d50\u679c<\/h2>\n\n\n\n<p>\u3053\u306e\u5b9f\u88c5\u3092\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u306e\u30d6\u30ed\u30b0\u306b\u5c0e\u5165\u3057\u307e\u3057\u305f\u3002\u7d50\u679c\u306f\u826f\u304b\u3063\u305f\u3067\u3059\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5e73\u5747\u8aad\u4e86\u7387\u304c\u7d0418%\u5411\u4e0a<\/li>\n\n\n\n<li>\u6b21\u30da\u30fc\u30b8\u3078\u306e\u9077\u79fb\u7387\u304c\u7d0412%\u5411\u4e0a<\/li>\n\n\n\n<li>\u76f4\u5e30\u7387\u304c\u7d049%\u6e1b\u5c11<\/li>\n<\/ul>\n\n\n\n<p>\u30af\u30e9\u30a4\u30a2\u30f3\u30c8\u3082\u300c\u30d7\u30ed\u30b0\u30ec\u30b9\u30d0\u30fc\u3088\u308a\u5727\u8feb\u611f\u304c\u306a\u3044\u300d\u3068\u559c\u3093\u3067\u304f\u308c\u307e\u3057\u305f\u3002\u8aad\u8005\u304b\u3089\u3082\u300c\u3069\u3053\u307e\u3067\u8aad\u3093\u3060\u304b\u5206\u304b\u308a\u3084\u3059\u3044\u300d\u3068\u3044\u3046\u58f0\u304c\u3042\u308a\u307e\u3057\u305f\u3002\u3061\u3087\u3063\u3068\u9762\u767d\u304b\u3063\u305f\u306e\u306f\u3001\u300c\u5168\u90e8\u306e\u70b9\u3092\u706f\u3057\u305f\u3044\u300d\u3068\u3044\u3046\u6c17\u6301\u3061\u3067\u6700\u5f8c\u307e\u3067\u8aad\u3080\u30e6\u30fc\u30b6\u30fc\u304c\u3044\u308b\u3053\u3068\u3067\u3059\u3002\u3053\u308c\u306f\u4e88\u60f3\u5916\u3067\u3057\u305f\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u5fdc\u7528\u3067\u304d\u308b\u30d1\u30bf\u30fc\u30f3<\/h2>\n\n\n\n<p>\u3053\u306e\u30c9\u30c3\u30c8\u9032\u6357\u306f\u3001\u30d6\u30ed\u30b0\u4ee5\u5916\u306b\u3082\u4f7f\u3048\u307e\u3059\u3002\u5b9f\u969b\u306b\u79c1\u304c\u8a66\u3057\u305f\u4f8b\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u30aa\u30f3\u30dc\u30fc\u30c7\u30a3\u30f3\u30b0\u753b\u9762<\/h3>\n\n\n\n<p>\u30a2\u30d7\u30ea\u306e\u521d\u56de\u5229\u7528\u6642\u306e\u8aac\u660e\u753b\u9762\u3067\u4f7f\u3044\u307e\u3057\u305f\u3002\u300c3\u30b9\u30c6\u30c3\u30d7\u5b8c\u4e86\u300d\u3068\u3044\u3046\u9054\u6210\u611f\u3092\u51fa\u305b\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. EC\u30b5\u30a4\u30c8\u306e\u5546\u54c1\u8aac\u660e<\/h3>\n\n\n\n<p>\u9577\u3044\u5546\u54c1\u8aac\u660e\u30da\u30fc\u30b8\u3067\u4f7f\u3044\u307e\u3057\u305f\u3002\u300c\u7279\u5fb4\u300d\u300c\u4ed5\u69d8\u300d\u300c\u30ec\u30d3\u30e5\u30fc\u300d\u306e3\u30bb\u30af\u30b7\u30e7\u30f3\u306b\u5bfe\u5fdc\u3059\u308b\u30c9\u30c3\u30c8\u3092\u8868\u793a\u3002\u3069\u3053\u307e\u3067\u898b\u305f\u304b\u5206\u304b\u308a\u3084\u3059\u304f\u306a\u308a\u307e\u3057\u305f\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. \u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u30b5\u30a4\u30c8<\/h3>\n\n\n\n<p>\u6280\u8853\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u3067\u4f7f\u3044\u307e\u3057\u305f\u3002\u8aad\u8005\u304c\u300c\u3069\u3053\u307e\u3067\u5b66\u7fd2\u3057\u305f\u304b\u300d\u3092\u8996\u899a\u7684\u306b\u78ba\u8a8d\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u5b9f\u88c5\u306e\u6ce8\u610f\u70b9<\/h2>\n\n\n\n<p>\u5b9f\u969b\u306b\u4f5c\u3063\u3066\u307f\u3066\u6c17\u3065\u3044\u305f\u6ce8\u610f\u70b9\u3092\u66f8\u3044\u3066\u304a\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u30c9\u30c3\u30c8\u306e\u6570\u306f\u591a\u3059\u304e\u306a\u3044<\/h3>\n\n\n\n<p>\u6700\u521d\u300110\u500b\u306e\u30c9\u30c3\u30c8\u3092\u8868\u793a\u3057\u307e\u3057\u305f\u3002\u3067\u3082\u591a\u3059\u304e\u3066\u898b\u3065\u3089\u304b\u3063\u305f\u3067\u3059\u30024\u301c6\u500b\u304c\u3061\u3087\u3046\u3069\u3044\u3044\u3068\u601d\u3044\u307e\u3059\u3002\u7ae0\u304c\u591a\u3044\u5834\u5408\u306f\u3001\u5927\u304d\u306a\u7ae0\u3060\u3051\u30c9\u30c3\u30c8\u3092\u4ed8\u3051\u308b\u306e\u304c\u3044\u3044\u3067\u3059\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u30e2\u30d0\u30a4\u30eb\u3067\u306e\u30b5\u30a4\u30ba\u8abf\u6574<\/h3>\n\n\n\n<p>\u30b9\u30de\u30db\u3067\u306f\u898b\u51fa\u3057\u304c\u9577\u3044\u3068\u3001\u30c9\u30c3\u30c8\u304c\u4e0b\u306b\u843d\u3061\u308b\u3053\u3068\u304c\u3042\u308a\u307e\u3059\u3002\u30ec\u30b9\u30dd\u30f3\u30b7\u30d6\u5bfe\u5fdc\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: css; title: ; notranslate\" title=\"\">\n@media (max-width: 640px) {\n  .chapter-header {\n    flex-direction: column;\n    align-items: flex-start;\n  }\n\n  .progress-dots {\n    margin-left: 0;\n    margin-top: 0.5rem;\n  }\n}\n<\/pre><\/div>\n\n\n<h3 class=\"wp-block-heading\">\u30a2\u30af\u30bb\u30b7\u30d3\u30ea\u30c6\u30a3\u306e\u914d\u616e<\/h3>\n\n\n\n<p>\u30b9\u30af\u30ea\u30fc\u30f3\u30ea\u30fc\u30c0\u30fc\u3092\u4f7f\u3046\u4eba\u306e\u305f\u3081\u306b\u3001\u30c9\u30c3\u30c8\u306b\u610f\u5473\u3092\u6301\u305f\u305b\u307e\u3059\u3002<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: xml; title: ; notranslate\" title=\"\">\n&lt;span class=&quot;dot&quot; data-dot=&quot;1&quot; aria-label=&quot;\u30bb\u30af\u30b7\u30e7\u30f31\u3092\u8aad\u4e86&quot; role=&quot;status&quot;&gt;&lt;\/span&gt;\n<\/pre><\/div>\n\n\n<p>\u70b9\u706f\u3057\u305f\u3068\u304d\u306b\u3001\u72b6\u614b\u304c\u4f1d\u308f\u308b\u3088\u3046\u306b\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u307e\u3068\u3081<\/h2>\n\n\n\n<p>\u30bb\u30af\u30b7\u30e7\u30f3\u9032\u6357\u306e\u30c9\u30c3\u30c8\u8868\u793a\u306b\u3064\u3044\u3066\u66f8\u304d\u307e\u3057\u305f\u3002\u30dd\u30a4\u30f3\u30c8\u306f\u4ee5\u4e0b\u306e3\u3064\u3067\u3059\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5e38\u6642\u8868\u793a\u3067\u306f\u306a\u304f\u300c\u6210\u679c\u306e\u30d5\u30a3\u30fc\u30c9\u30d0\u30c3\u30af\u300d\u3068\u3057\u3066\u4f7f\u3046<\/li>\n\n\n\n<li>IntersectionObserver\u3067\u7ae0\u306e\u8868\u793a\u3092\u76e3\u8996\u3059\u308b<\/li>\n\n\n\n<li>\u4e00\u5ea6\u70b9\u706f\u3057\u305f\u30c9\u30c3\u30c8\u306f\u6d88\u3048\u306a\u3044\uff08\u8aad\u3093\u3060\u8a3c\u62e0\u3068\u3057\u3066\u6b8b\u308b\uff09<\/li>\n<\/ul>\n\n\n\n<p>\u5b9f\u88c5\u306f\u30b7\u30f3\u30d7\u30eb\u3067\u3059\u304c\u3001\u52b9\u679c\u306f\u5927\u304d\u3044\u3067\u3059\u3002\u3061\u3087\u3063\u3068\u3057\u305f\u3053\u3068\u3060\u3051\u3069\u3001\u304a\u5ba2\u69d8\u306f\u559c\u3073\u307e\u3059\u3002\u682a\u5f0f\u4f1a\u793e\u30d5\u30a1\u30b9\u30c8\u30b3\u30fc\u30c7\u30a3\u30f3\u30b0\u3067\u306f\u3001\u3053\u3046\u3057\u305f\u8aad\u4e86\u7387\u6539\u5584\u306e\u5b9f\u88c5\u30b5\u30dd\u30fc\u30c8\u3082\u884c\u3063\u3066\u3044\u307e\u3059\u3002\u30d6\u30ed\u30b0\u3084\u30c9\u30ad\u30e5\u30e1\u30f3\u30c8\u30b5\u30a4\u30c8\u306e\u30e6\u30fc\u30b6\u30fc\u4f53\u9a13\u3092\u826f\u304f\u3057\u305f\u3044\u65b9\u306f\u3001<a href=\"https:\/\/fastcoding.jp\/contact\/\">\u304a\u554f\u3044\u5408\u308f\u305b\u30d5\u30a9\u30fc\u30e0<\/a>\u304b\u3089\u3054\u9023\u7d61\u304f\u3060\u3055\u3044\u3002<\/p>\n\n\n\n<p class=\"has-small-font-size\">\u203b\u672c\u8a18\u4e8b\u306f\u5f0a\u793e\u5916\u56fd\u4eba\u30b9\u30bf\u30c3\u30d5\u306b\u3088\u308b\u6295\u7a3f\u3067\u3059\u3002\u8a00\u3044\u56de\u3057\u3084\u8868\u73fe\u304c\u4e0d\u5341\u5206\u306a\u500b\u6240\u304c\u3042\u308a\u307e\u3059\u3053\u3068\u3054\u5bb9\u8d66\u3044\u305f\u3060\u304d\u307e\u3059\u3088\u3046\u304a\u9858\u3044\u3044\u305f\u3057\u307e\u3059\u3002<br>\u682a\u5f0f\u4f1a\u793e\u30d5\u30a1\u30b9\u30c8\u30b3\u30fc\u30c7\u30a3\u30f3\u30b0<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>\u30d6\u30ed\u30b0\u8a18\u4e8b\u306e\u8aad\u4e86\u7387\u309218%\u5411\u4e0a\u3055\u305b\u305f\u30bb\u30af\u30b7\u30e7\u30f3\u9032\u6357\u8868\u793a\u306e\u5b9f\u88c5\u65b9\u6cd5\u3002IntersectionObserver API\u3092\u4f7f\u3044\u3001\u8aad\u3093\u3060\u7b87\u6240\u3092\u70b9\uff08\u30c9\u30c3\u30c8\uff09\u3067\u53ef\u8996\u5316\u3002\u30d7\u30ed\u30b0\u30ec\u30b9\u30d0\u30fc\u3088\u308a\u5727\u8feb\u611f\u304c\u306a\u304f\u3001\u9054\u6210\u611f\u3092\u4e0e\u3048\u307e\u3059\u3002HTML\/CSS\/JavaScript\u306e\u30b3\u30fc\u30c9\u4ed8\u304d\u3002<\/p>\n","protected":false},"author":21,"featured_media":9379,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"enabled":false},"version":2}},"categories":[316],"tags":[33,32,22,320],"class_list":["post-9357","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ui-ux","tag-css","tag-html","tag-javascript","tag-ui-ux"],"acf":[],"aioseo_notices":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/fastcoding.jp\/blog\/wp-content\/uploads\/2025\/11\/0904b5a9a5723db1c01fc37724ef3f5c.png","jetpack_sharing_enabled":true,"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/posts\/9357","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/users\/21"}],"replies":[{"embeddable":true,"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/comments?post=9357"}],"version-history":[{"count":2,"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/posts\/9357\/revisions"}],"predecessor-version":[{"id":9378,"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/posts\/9357\/revisions\/9378"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/media\/9379"}],"wp:attachment":[{"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/media?parent=9357"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/categories?post=9357"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fastcoding.jp\/blog\/wp-json\/wp\/v2\/tags?post=9357"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}