OffscreenCanvasinterface provides a canvas that can be rendered off screen. It is available in both the window and worker contexts.
PerformanceEntryobject encapsulates a single performance metric that is part of the performance timeline. A performance entry can be directly created by making a performance
measure(for example by calling the
mark()method) at an explicit point in an application. Performance entries are also created in indirect ways such as loading a resource (such as an image).
PerformanceFrameTiminginterface provides frame timing data about the browser's event loop. A frame represents the amount of work a browser does in one event loop such as processing DOM events, resizing, scrolling, rendering, CSS animations, etc. A frame rate of 60fps (frames per second) for a 60Hz refresh rate is the target for a good responsive user experience. This means the browser should process a frame in about 16.7ms.
PerformanceNavigationTiminginterface provides methods and properties to store and retrieve
high resolution timestampsor metrics regarding the browser's document navigation events. For example, this interface can be used to determine how much time it takes to load or unload a document.
PerformanceObserverinterface is used to observe performance measurement events and be notified of new performance entries as they are recorded in the browser's performance timeline.
PerformanceResourceTiminginterface enables retrieving and analyzing detailed network timing data regarding the loading of an application's resources. An application can use the timing metrics to determine, for example, the length of time it takes to fetch a specific resource, such as an
<SVG>, image, or script.
Selection.toString()method returns the text contained in the selection, e.g.:
UIEventinterface represents simple user interface events.
WebGLTransformFeedbackinterface is part of the WebGL 2 API and enables transform feedback, which is the process of capturing primitives generated by vertex processing. It allows to preserve the post-transform rendering state of an object and resubmit this data multiple times.