在此页

• 句法
• 范例
• 规范
• 浏览器兼容性
• 相关话题

这是 实验性技术
检查 浏览器兼容性表格 要小心谨慎在生产中使用这之前。

allowsFeature() 方法在 FeaturePolicy interface enables introspection of individual directives of the Feature Policy it is run on. It returns a 布尔 也就是 true if and only if the specified feature is allowed in the specified context (or the default context if no context is specified).

句法

const allowed = FeaturePolicy.allowsFeature(<feature>)
					

or

const allowed = FeaturePolicy.allowsFeature(<feature>, <origin>)
					

参数

Feature name

A specific feature name must be specified.

Origin name 可选

An origin URL to check the feature on. If it is omitted the default origin is used.

返回值

A 布尔 也就是 true if and only if the feature is allowed.

范例

The following example queries whether or not the document is allowed to use camera API by the Feature Policy. Please note that Camera API might be restricted by the Permissions API, if the user did not grant the corresponding permission yet.

// First, get the Feature Policy object
const featurePolicy = document.featurePolicy
// Then query feature for specific
const allowed = featurePolicy.allowsFeature("camera")
if (allowed){
  console.log("FP allows camera.")
} else {
  console.log("FP does not allows camera.")
}
					

规范

规范	状态	注释
Feature Policy The definition of 'allowsFeature' in that specification.	编者草案	初始定义。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
allowsFeature	Chrome 74 74 不支持 69 — 73 Disabled Disabled ). To change preferences in Chrome, visit	Edge 79	Firefox 65	IE No	Opera 62 62 不支持 56 — 62 Disabled Disabled From version 56 until version 62 (exclusive): this feature is behind the #enable-experimental-productivity-features preference (needs to be set to 启用 ).	Safari No	WebView Android 74	Chrome Android 74 74 不支持 69 — 74 Disabled Disabled ). To change preferences in Chrome, visit	Firefox Android 65	Opera Android 48 Disabled 48 Disabled Disabled From version 48: this feature is behind the #enable-experimental-productivity-features preference (needs to be set to 启用 ).	Safari iOS No	Samsung Internet Android 11.0

图例

完整支持

完整支持

不支持

不支持

实验。期望将来行为有所改变。

实验。期望将来行为有所改变。

用户必须明确启用此特征。

用户必须明确启用此特征。

元数据

• 最后修改： Jan 29, 2020

相关话题

1. FeaturePolicy