4.2 Extensions to the Performance Interface

partial interface Performance {
    void clearFrameTimings ();
    void setFrameTimingBufferSize (unsigned long maxSize);
                attribute EventHandler onframetimingbufferfull;
};

4.3 The PerformanceRenderTiming Interface

The PerformanceRenderTiming interface participates in the Performance Timeline and extends the following attributes of the PerformanceEntry interface [Performance-Timeline]:

name

This attribute MUST return the current document's address.

entryType

This attribute MUST return the DOMString "render".

startTime

This attribute MUST return a DOMHighResTimeStamp with current frame's beginning time value, which is the time that the requestAnimationFrame callback (see [Animation-Timing]) would have fired for the frame. [HR-Time].

duration

This attribute MUST return a DOMHighResTimeStamp with the difference between the end of the frame and the startTime of the frame. The end of the frame is defined as what the beginning time of the next frame's requestAnimationFrame callback (see [Animation-Timing]) would have been, had one been scheduled in the current frame. If a requestAnimationFrame is already requested, its beginning time SHOULD be used.

interface PerformanceRenderTiming : PerformanceEntry {
    readonly    attribute unsigned long sourceFrameNumber;
    serializer = {inherit, attribute};
};

4.4 The PerformanceCompositeTiming Interface

The PerformanceCompositeTiming interface participates in the Performance Timeline and extends the following attributes of the PerformanceEntry interface [Performance-Timeline]:

name

This attribute MUST return the name of the requesting document.

entryType

This attribute MUST return the DOMString "composite".

startTime

This attribute MUST return a DOMHighResTimeStamp with the event's time value [HR-Time].

duration

The duration attribute MUST return a DOMHighResTimeStamp of value 0.

interface PerformanceCompositeTiming : PerformanceEntry {
    readonly    attribute unsigned long sourceFrameNumber;
    serializer = {inherit, attribute};
};