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    Performance

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    The Performance interface represents timing-related performance information for the given page.

    An object of this type can be obtained by calling the Window.performance read-only attribute.

    Note: This interface and its members are available in Web Workers, except where indicated below. Note that some available parts of the interface are not yet documented (see the Performance Timeline and User Timing specs for more details.) Also note that performance markers and measures are per context. If you create a mark on the main thread (or other worker), you cannot see it in a worker thread, and vice versa.

    Properties

    The Performance interface doesn't inherit any property.

    Performance.timing Read only Not available to workers
    Is a PerformanceTiming object containing latency-related performance information.
    Performance.navigation Read only Not available to workers
    Is a PerformanceNavigation object representing the type of navigation that occurs in the given browsing context, like the amount of redirections needed to fetch the resource.

    Methods

    The Performance interface doesn't inherit any method.

    Performance.now()
    Returns a DOMHighResTimeStamp representing the amount of milliseconds elapsed since a reference instant.
    Performance.toJSON() Not available to workers
    Is a jsonizer returning a json object representing the Performance object.

    Specifications

    Specification Status Comment
    High Resolution Time
    The definition of 'Performance' in that specification.
    Recommendation Added the now() method.
    Navigation Timing
    The definition of 'Performance' in that specification.
    Recommendation Initial definition.

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
    Basic support (timing attribute) 6.0 7.0 (7.0) 9.0 15.0 8
    navigation attribute Not supported Not supported 9.0 Not supported 8
    now() on regular context 20.0 webkit
    24.0
    15.0 (15.0) 10.0 (Yes) 8
    now() in Web workers. 33.0 34.0 (34.0) ? (Yes) ?
    toJSON() Not supported 25.0 (25.0) 9.0 Not supported ?
    Feature Android Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
    Basic support Not supported 7.0 (7.0) 1.0 (7.0) 9.0 15.0 Not supported
    navigation attribute Not supported Not supported Not supported 9.0 Not supported Not supported
    now() on regular context 20.0 webkit
    24.0
    15.0 (15.0) 1.0 (15.0) 10.0 Not supported Not supported
    now() in Web workers. ? 34.0 (34.0) ? ? ? ?
    toJSON() Not supported 25.0 (25.0) 1.2 (25.0) 9.0 Not supported Not supported

    See also

    ドキュメントのタグと貢献者

    Contributors to this page: fscholz, teoli, Bzbarsky, chrisdavidmills, adria, zanona
    最終更新者: chrisdavidmills,