Performance 接口可以获取到当前页面中与性能相关的信息。它是 High Resolution Time API 的一部分，同时也融合了 Performance Timeline API、Navigation Timing API、 User Timing API 和 Resource Timing API。
该类型的对象可以通过调用只读属性 Window.performance 来获得。
注意：除了以下指出的情况外，该接口及其成员在 Web Worker 中可用。此外，还需注意，performance 的创建和衡量都是同一环境下的。即，如果你在主线程（或者其他 worker）中创建了一个 performance，那么它在另外的 worker 线程中是不可用的；反之亦然。
属性
Performance 接口没有继承任何属性。
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Performance.navigation只读 Not available to workers PerformanceNavigation对象提供了在指定的时间段里发生的操作相关信息，包括页面是加载还是刷新、发生了多少次重定向等等。-
Performance.timing只读 Not available to workers PerformanceTiming对象包含延迟相关的性能信息。performance.memory- 其是 Chrome 添加的一个非标准扩展，这个属性提供了一个可以获取到基本内存使用情况的对象。不应该使用这个非标准的 API。
Performance.timeOrigin只读- 返回性能测量开始时的时间的高精度时间戳。
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事件处理程序
Performance.onresourcetimingbufferfull- 一个回调的
EventTarget，当触发resourcetimingbufferfull事件的时候会被调用。
方法
Performance 接口没有继承任何方法。
Performance.clearMarks()- 将给定的 mark 从浏览器的性能输入缓冲区中移除。
Performance.clearMeasures()- 将给定的 measure 从浏览器的性能输入缓冲区中。
Performance.clearResourceTimings()- 从浏览器的性能数据缓冲区中移除所有
entryType是 "resource" 的performance entries。 Performance.getEntries()- 基于给定的 filter 返回一个
PerformanceEntry对象的列表。 Performance.getEntriesByName()- 基于给定的 name 和 entry type 返回一个
PerformanceEntry对象的列表。 Performance.getEntriesByType()- 基于给定的 entry type 返回一个
PerformanceEntry对象的列表 Performance.mark()- 根据给出 name 值，在浏览器的性能输入缓冲区中创建一个相关的
timestamp Performance.measure()- 在浏览器的指定 start mark 和 end mark 间的性能输入缓冲区中创建一个指定的
timestamp Performance.now()- 返回一个表示从性能测量时刻开始经过的毫秒数
DOMHighResTimeStamp Performance.setResourceTimingBufferSize()- 将浏览器的资源 timing 缓冲区的大小设置为 "
resource"typeperformance entry对象的指定数量 Performance.toJSON()Not available to workers- 其是一个 JSON 格式转化器，返回
Performance对象的 JSON 对象
规范
| Specification | Status | Comment |
|---|---|---|
| High Resolution Time Level 3 timeOrigin |
Editor's Draft | Defines timeOrigin property. |
| High Resolution Time Level 2 toJSON() |
Candidate Recommendation | Defines toJson() method. |
| High Resolution Time Performance |
Recommendation | Defines now() method. |
| Navigation Timing Performance |
Recommendation | Defines timing and navigation properties. |
| Performance Timeline Level 2 Performance extensions |
Candidate Recommendation | Changes getEntries() interface. |
| Performance Timeline Performance extensions |
Recommendation | Defines getEntries(), getEntriesByType() and getEntriesByName() methods. |
| Resource Timing Level 1 Performance extensions |
Candidate Recommendation | Defines clearResourceTimings() and setResourceTimingBufferSize() methods and the onresourcetimingbufferfull property. |
| User Timing Level 2 Performance extensions |
Working Draft | Clarifies mark(), clearMark(), measure() and clearMeasure() methods. |
| User Timing Performance extensions |
Recommendation | Defines mark(), clearMark(), measure() and clearMeasure() methods. |
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.
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 6 | Yes | 7 | 9 | 15 | 8 |
clearMarks | 43 | Yes | 41 | 10 | 33 | 11 |
clearMeasures | 43 | Yes | 41 | 10 | 33 | 11 |
clearResourceTimings | 46 Yes — 57 webkit | Yes | Yes | Yes | Yes | 11 |
getEntries | Yes | Yes | Yes | Yes | No | 11 |
getEntriesByName | Yes | Yes | Yes | Yes | No | 11 |
getEntriesByType | Yes | Yes | Yes | Yes | No | 11 |
mark | 43 | Yes | 41 | 10 | 33 | 11 |
measure | 43 | Yes | 41 | 10 | 33 | 11 |
memory | Yes | ? | No | ? | Yes | No |
navigation | 10 | Yes | 7 | 9 | 15 | 8 |
now | 24 | Yes | 151 2 | 10 | 15 | 8 |
onresourcetimingbufferfull | 46 Yes — 57 webkit | ? | Yes | No | No | No |
setResourceTimingBufferSize | 46 Yes — 57 webkit | Yes | Yes | Yes | Yes | No |
timeOrigin | 62 | ? | 59 | ? | 49 | No |
timing | 6 | Yes | 7 | 9 | 15 | 8 |
toJSON | No | Yes | 25 | ? | No | No |
| Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | Opera Android | iOS Safari | Samsung Internet |
|---|---|---|---|---|---|---|---|
| Basic support | Yes | Yes | Yes | 7 | 15 | 9 | ? |
clearMarks | 46 | 46 | Yes | 42 | 33 | 11 | ? |
clearMeasures | 46 | 46 | Yes | 42 | 33 | 11 | ? |
clearResourceTimings | 46 Yes — 57 webkit | 46 Yes — 57 webkit | Yes | Yes | Yes | 11 | ? |
getEntries | Yes | Yes | Yes | 25 | No | 11 | ? |
getEntriesByName | Yes | Yes | Yes | 25 | No | 11 | ? |
getEntriesByType | Yes | Yes | Yes | 25 | No | 11 | ? |
mark | 46 | 46 | Yes | 42 | 33 | 11 | ? |
measure | 46 | 46 | Yes | 42 | 33 | 11 | ? |
memory | Yes | Yes | ? | No | Yes | No | ? |
navigation | Yes | Yes | Yes | 7 | No | 9 | ? |
now | 25 | 25 | Yes | 151 2 | No | 9 | ? |
onresourcetimingbufferfull | 46 Yes — 57 webkit | 46 Yes — 57 webkit | ? | Yes | Yes | No | ? |
setResourceTimingBufferSize | 46 Yes — 57 webkit | 46 Yes — 57 webkit | Yes | Yes | Yes | No | ? |
timeOrigin | 62 | 62 | ? | 59 | 49 | No | ? |
timing | Yes | Yes | Yes | 7 | 15 | 9 | ? |
toJSON | No | No | Yes | 25 | No | No | ? |
1. In Firefox 57.0.4 the accuracy was reduced to 20 microseconds.
2. In Firefox 59 the accuracy was reduced to 2 milliseconds.