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Document: firstElementChild プロパティ - Web API | MDN
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Document: firstElementChild プロパティ
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2018年4月.
Document.firstElementChild は読み取り専用プロパティで、この文書の最初の子要素 (Element) を返します。子要素がなければ null を返します。
HTML 文書においては、これは普通は唯一の子である、ルートの <html> 要素です。
文書内の特定の要素における最初の子要素については、 Element.firstElementChild を参照してください。
値
Element オブジェクト、または null です。
例
js
document.firstElementChild;
// この文書の唯一の子でである、ルート <html> 要素を返す
仕様書
| Specification |
|---|
| DOM # ref-for-dom-parentnode-firstelementchild① |
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