* 仕様書

[REFS[
- [4] [CITE@en-GB-x-hixie[HTML Standard]] ([TIME[2016-05-14 09:55:50 +09:00]]) <https://html.spec.whatwg.org/#concept-custom-element-definition-prototype>
]REFS]

* [F[プロトタイプ]] (カスタム要素定義)

[5] [[カスタム要素定義]]は、[DFN[[F[[RUBYB[[[プロトタイプ]]]@en[prototype]]]]]]を持ちます。
[F[プロトタイプ]]は、 [[JavaScript]] の[[オブジェクト]]です。 [SRC[>>4]]

* 関連

[3] [[プロトタイプ]]を用いる[[オブジェクト指向]]を特に[[プロトタイプ型]]と呼んで[[クラス型オブジェクト指向]]と区別します。

[2] [[JavaScript]] [[ライブラリー]]である [[Prototype.js]] は [[JavaScript]] [[言語]]の概念である「[[プロトタイプ]]」
と直接の関係はありません。

* 歴史

[FIG(quote)[
[FIGCAPTION[
[1] [CITE[ECMAScript Language Specification (HTML version)]] ([TIME[2009-04-03 04:43:48 +09:00]] 版) <http://bclary.com/2004/11/07/#a-4.3.5>
]FIGCAPTION]

>A [DFN@en[prototype]] is an [[object]] used to implement structure, state, and behaviour inheritance in [[ECMAScript]].
When a [[constructor]] creates an [[object]], that [[object]] implicitly references the [[constructor]]'s associated
[[prototype]] for the purpose of resolving [[property]] references. The [[constructor]]'s associated [[prototype]]
can be referenced by the [[program]] [[expression]] [CODE(JS)@en[[[constructor]].[[prototype]]]], and [[properties]]
added to an [[object]]'s [[prototype]] are shared, through [[inheritance]], by all [[objects]] sharing the [[prototype]].
]FIG]


[6] [CITE@en[Revamp interface bindings (#313)]]
([[tobie]]著, [TIME[2017-02-21 07:17:07 +09:00]])
<https://github.com/heycam/webidl/commit/4a8f57e276369db7ea5fb09974a09b0ca5d276dd>