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。
PerformanceFrameTiming
接口提供
frame
计时数据有关浏览器的事件循环。
frame
表示浏览器所做的工作量在
一事件循环迭代
譬如：处理 DOM 事件、重置尺寸、卷动、渲染、CSS 动画等。
帧速率
of 60 fps (frames per second) for a 60 Hz refresh rate is a common target for a good
responsive
user experience. This means the browser should process a frame in about 16.7 ms.
An application can register a
PerformanceObserver
for "
frame
"
performance entry types
。
observer
(callback) will be notified when new "
frame
" events are added to the browser's
performance timeline
and the frame's
duration
(length of time) will be available. This data can be used to help identify areas that take too long to provide a good user experience.
Example code of the interfaces described in this document is included in 使用帧计时 API .
frames
PerformanceFrameTiming
interface extends the following
PerformanceEntry
properties (for "
frame
"
performance entry types
) by qualifying and constrainting the properties as follows:
PerformanceEntry.entryType
frame
".
PerformanceEntry.name
PerformanceEntry.startTime
DOMHighResTimeStamp
when the frame was started.
PerformanceEntry.duration
timestamp
indicating the difference between the
startTime
s of two successive frames.
This data, particularly the
duration
timestamp, can be used to help identify performance problems.
性能观测器
interfaces allow an application to register an
observer
for specific
performance event types
. When one of those event types is recorded in the browser's
performance timeline
, the application is notified of the event via the observer's callback function that was specified when the observer was created.
To observe "
frame
" performance entry types, the application first creates a
PerformanceObserver
object with a specific frame observer callback (function). Next,
PerformanceObserver.observe()
is used to specify the set of performance events to observe - in this case, just the "
frame
" event type. When the browser adds a new frame to the performance timeline, the specified observer callback will be invoked.
When a frame
observer
is invoked, frame
performance entries
can be retrieved by calling
PerformanceObserverEntryList.getEntriesByType()
with an argument of "
frame
". This method returns a list of "
frame
"
PerformanceEntry
objects. Each frame object's
duration
property returns the timestamp of two consecutive frames. If this value is greater than the time needed to provide a good user experience, further analysis might be warranted.
As shown in the
PerformanceFrameTiming
接口的
浏览器兼容性
table, this interface has no implementations.