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The timeline events mode displays all events triggered while making a recording. Use the timeline event reference to learn more about each timeline event type.
Common timeline event properties
Certain details are present in events of all types, while some only apply to certain event types. This section lists properties common to different event types. Properties specific to certain event types are listed in the references for those event types that follow.
When is it shown
For events with nested events, the time taken by each category of events.
For events with child events, the time taken by each category of events.
How much CPU time the recorded event took.
Other details about the event.
Duration (at time-stamp)
How long it took the event with all of its children to complete; timestamp is the time at which the event occurred, relative to when the recording started.
How long the event took without any of its children.
Used Heap Size
Amount of memory being used by the application when the event was recorded, and the delta (+/-) change in used heap size since the last sampling.
This section lists events that belong to Loading category and their properties.
Chrome executed its HTML parsing algorithm.
A network request completed.
Data for a request was received. There will be one or more Receive Data events.
The initial HTTP response from a request.
A network request has been sent.
Loading event properties
The URL of the requested resource.
Preview of the requested resource (images only).
HTTP method used for the request (GET or POST, for example).
HTTP response code.
MIME type of the requested resource.
Encoded Data Length
Length of requested resource in bytes.
This section lists events that belong to the Scripting category and their properties.
Animation Frame Fired
A scheduled animation frame fired, and its callback handler invoked.
Cancel Animation Frame
A scheduled animation frame was canceled.
Garbage collection occurred.
The DOMContentLoaded was fired by the browser. This event is fired when all of the page’s DOM content has been loaded and parsed.
A script was evaluated.
A timer fired that was scheduled with setInterval() or setTimeout().
XHR Ready State Change
The ready state of an XMLHTTPRequest changed.
An XMLHTTPRequest finished loading.
Scripting event properties
The timer ID.
The timeout specified by the timer.
Boolean that specifies if the timer repeats.
A function that was invoked.
This section lists events that belong to Rendering category and their properties.
The page layout was invalidated by a DOM change.
A page layout was executed.
Chrome recalculated element styles.
The content of nested view was scrolled.
Rendering event properties
For Layout records, the stack trace of the code that caused the layout to be invalidated.
Nodes that need layout
For Layout records, the number of nodes that were marked as needing layout before the relayout started. These are normally those nodes that were invalidated by developer code, plus a path upward to relayout root.
Layout tree size
For Layout records, the total number of nodes under the relayout root (the node that Chrome starts the relayout).
Possible values are "Partial" (the re-layout boundary is a portion of the DOM) or "Whole document".
For Recalculate style records, the number of elements affected by a style recalculation.
For Recalculate style records, provides the stack trace of the code that caused the style invalidation.
This section lists events that belong to Painting category and their properties.