自定义元素注册表

草案
本页尚未完工.

CustomElementRegistry接口提供注册自定义元素和查询已注册元素的方法。

这是一个实验中的功能
此功能某些浏览器尚在开发中，请参考浏览器兼容性表格以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订，所以在未来版本的浏览器中该功能的语法和行为可能随之改变。

方法

CustomElementRegistry.define(): 定义一个新的自定义元素。
CustomElementRegistry.get(): 返回指定自定义元素的构造函数，如果未定义自定义元素，则返回undefined。
CustomElementRegistry.whenDefined(): 返回当使用给定名称定义自定义元素时将会执行的promise。（如果已经定义了这样一个自定义元素，那么立即履行返回的 promise。）

示例

JS 文件：

// `window.customElements` is an instance of `CustomElementRegistry`
window.customElements instanceof CustomElementRegistry // true

规范

Specification	Status	Comment
HTML Living Standard CustomElementRegistry	Living Standard	Initial definition.

Feature	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	54	No¹	59² Yes — 59³	No	41	10.1
Support for Customized built-in elements	66	No	59² Yes — 59³	No	53	No
`define`	66⁴ 54⁵	No¹	59² Yes — 59³	No	53⁴ 41⁵	10.1⁶
`get`	66⁴ 54⁵	No¹	59² Yes — 59³	No	53⁴ 41⁵	10.1⁶
`whenDefined`	66⁴ 54⁵	No¹	59² Yes — 59³	No	53⁴ 41⁵	10.1⁶

Feature	Android webview	Chrome for Android	Edge mobile	Firefox for Android	Opera Android	iOS Safari	Samsung Internet
Basic support	54	54	No¹	59² Yes — 59³	41	10.1	6.0
Support for Customized built-in elements	66	66	No	59² Yes — 59³	53	No	No
`define`	66⁴ 54⁵	66⁴ 54⁵	No¹	59² Yes — 59³	53⁴ 41⁵	10.1⁶	6.0⁵
`get`	66⁴ 54⁵	66⁴ 54⁵	No¹	59² Yes — 59³	53⁴ 41⁵	10.1⁶	6.0⁵
`whenDefined`	66⁴ 54⁵	66⁴ 54⁵	No¹	59² Yes — 59³	53⁴ 41⁵	10.1⁶	6.0⁵

1. Under consideration

2. From version 59: this feature is behind the dom.webcomponents.customelements.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

3. Until version 59 (exclusive): this feature is behind the dom.webcomponents.enabled preference (needs to be set to true) and the dom.webcomponents.customelements.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

4. Support for 'Customized built-in elements' as well.

5. Support for 'Autonomous custom elements' only.

6. Supports 'Autonomous custom elements' but not 'Customized built-in elements'

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Edge Mobile	Firefox for Android	Opera for Android	iOS Safari	Samsung Internet
Basic support Experimental	Full support 54	No support No Notes No support No Notes Notes Under consideration	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	No support No	Full support 41	Full support 10.1	Full support 54	Full support 54	No support No Notes No support No Notes Notes Under consideration	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Full support 41	Full support 10.1	Full support 6.0
Support for Customized built-in elements Experimental	Full support 66	No support No	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	No support No	Full support 53	No support No	Full support 66	Full support 66	No support No	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Full support 53	No support No	No support No
`define` Experimental	Full support 66 Notes Full support 66 Notes Notes Support for 'Customized built-in elements' as well. Full support 54 Notes Notes Support for 'Autonomous custom elements' only.	No support No Notes No support No Notes Notes Under consideration	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	No support No	Full support 53 Notes Full support 53 Notes Notes Support for 'Customized built-in elements' as well. Full support 41 Notes Notes Support for 'Autonomous custom elements' only.	Full support 10.1 Notes Full support 10.1 Notes Notes Supports 'Autonomous custom elements' but not 'Customized built-in elements'	Full support 66 Notes Full support 66 Notes Notes Support for 'Customized built-in elements' as well. Full support 54 Notes Notes Support for 'Autonomous custom elements' only.	Full support 66 Notes Full support 66 Notes Notes Support for 'Customized built-in elements' as well. Full support 54 Notes Notes Support for 'Autonomous custom elements' only.	No support No Notes No support No Notes Notes Under consideration	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Full support 53 Notes Full support 53 Notes Notes Support for 'Customized built-in elements' as well. Full support 41 Notes Notes Support for 'Autonomous custom elements' only.	Full support 10.1 Notes Full support 10.1 Notes Notes Supports 'Autonomous custom elements' but not 'Customized built-in elements'	Full support 6.0 Notes Full support 6.0 Notes Notes Support for 'Autonomous custom elements' only.
`get` Experimental	Full support 66 Notes Full support 66 Notes Notes Support for 'Customized built-in elements' as well. Full support 54 Notes Notes Support for 'Autonomous custom elements' only.	No support No Notes No support No Notes Notes Under consideration	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	No support No	Full support 53 Notes Full support 53 Notes Notes Support for 'Customized built-in elements' as well. Full support 41 Notes Notes Support for 'Autonomous custom elements' only.	Full support 10.1 Notes Full support 10.1 Notes Notes Supports 'Autonomous custom elements' but not 'Customized built-in elements'	Full support 66 Notes Full support 66 Notes Notes Support for 'Customized built-in elements' as well. Full support 54 Notes Notes Support for 'Autonomous custom elements' only.	Full support 66 Notes Full support 66 Notes Notes Support for 'Customized built-in elements' as well. Full support 54 Notes Notes Support for 'Autonomous custom elements' only.	No support No Notes No support No Notes Notes Under consideration	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Full support 53 Notes Full support 53 Notes Notes Support for 'Customized built-in elements' as well. Full support 41 Notes Notes Support for 'Autonomous custom elements' only.	Full support 10.1 Notes Full support 10.1 Notes Notes Supports 'Autonomous custom elements' but not 'Customized built-in elements'	Full support 6.0 Notes Full support 6.0 Notes Notes Support for 'Autonomous custom elements' only.
`whenDefined` Experimental	Full support 66 Notes Full support 66 Notes Notes Support for 'Customized built-in elements' as well. Full support 54 Notes Notes Support for 'Autonomous custom elements' only.	No support No Notes No support No Notes Notes Under consideration	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	No support No	Full support 53 Notes Full support 53 Notes Notes Support for 'Customized built-in elements' as well. Full support 41 Notes Notes Support for 'Autonomous custom elements' only.	Full support 10.1 Notes Full support 10.1 Notes Notes Supports 'Autonomous custom elements' but not 'Customized built-in elements'	Full support 66 Notes Full support 66 Notes Notes Support for 'Customized built-in elements' as well. Full support 54 Notes Notes Support for 'Autonomous custom elements' only.	Full support 66 Notes Full support 66 Notes Notes Support for 'Customized built-in elements' as well. Full support 54 Notes Notes Support for 'Autonomous custom elements' only.	No support No Notes No support No Notes Notes Under consideration	Full support 59 Disabled Full support 59 Disabled Disabled From version 59: this feature is behind the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config. No support ? — 59 Disabled Disabled Until version 59 (exclusive): this feature is behind the `dom.webcomponents.enabled` preference (needs to be set to `true`) and the `dom.webcomponents.customelements.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	Full support 53 Notes Full support 53 Notes Notes Support for 'Customized built-in elements' as well. Full support 41 Notes Notes Support for 'Autonomous custom elements' only.	Full support 10.1 Notes Full support 10.1 Notes Notes Supports 'Autonomous custom elements' but not 'Customized built-in elements'	Full support 6.0 Notes Full support 6.0 Notes Notes Support for 'Autonomous custom elements' only.

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.: Experimental. Expect behavior to change in the future.
See implementation notes.: See implementation notes.
User must explicitly enable this feature.: User must explicitly enable this feature.

自定义元素注册表

方法

示例

规范

浏览器兼容

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