January 2017
Intermediate to advanced
452 pages
5h 53m
Japanese
Content preview from 初めてのJavaScript 第3版 ―ES2015以降の最新ウェブ開発Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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18章ウェブブラウザのJavaScript
JavaScriptはウェブブラウザ用のスクリプト言語として誕生し、現在もその地位を独占しています。この章ではブラウザ環境でのJavaScriptについて説明します。言語としてのJavaScriptはどの環境でも共通ですが、利用できるオブジェクトなどについては環境ごとに異なりますので注意が必要です。
ここではブラウザベースのJavaScriptの基礎的な概念を紹介します。より詳しくは参考文献などを参照してください。
18.1 ES5かES2015か
サーバーサイドの場合、JavaScriptを実行する「エンジン」は開発者が自由に決めることができますが、クライアントサイドではユーザーがどのブラウザを利用するかを開発者が指定することはできません。したがって、しばらくの間はクライアント側スクリプトの開発をES2015で行う場合には「トランスパイル」が必要になります。（ES2015の対応が十分になるまでは）ウェブに公開するコードを書く場合には、 「1章 JavaScriptの歴史と開発環境」や「付録C 開発ツールのインストール」で紹介している手順に従って、トランスパイルを行ってから公開してください。
18.2 ドキュメントオブジェクトモデル（DOM）
ドキュメントオブジェクトモデル（Document Object Model：DOM）はHTMLドキュメントの構造を記述するもので、これを使ってブラウザとのやり取りを行い、表示をコントロールすることができます。
DOMは木構造になっており、木構造の各要素は「ノード」と呼ばれます。最上位ノードを除き必ず親ノードをもち、0個以上の「子ノード」をもちます。DOMのルートノードはdocument ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.