Most of today's web content assumes the user's pointing device will be a mouse. However, since many devices support other types of pointing input devices, such as pen/stylus and touch surfaces, extensions to the existing pointing device event models are needed and pointer events address that need.
The PerformanceFrameTiming interface provides frame timing data about the browser's event loop. A frame represents the amount of work a browser does in one event loop iteration such as processing DOM events, resizing, scrolling, rendering, CSS animations, etc. A frame rate 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.
The Performance Timeline API defines extensions to the Performance interface to support client-side latency measurements within applications. The extensions provide interfaces to retrieve performance entry metrics based on specific filter criteria. The standard also includes interfaces that allow an application to define performance observer callbacks that are notified when specific performance events are added to the browser's performance timeline.
The Resource Timing interfaces enable retrieving and analyzing detailed network timing data regarding the loading of an application's resource(s). An application can use the timing metrics to determine, for example, the length of time it takes to load a specific resource, such as an XMLHttpRequest, <SVG>, image, or script.
CSS Fonts is a module of CSS that defines font-related properties and how font resources are loaded. It allows to define the style of a font, like its family, its size or its weight, and the variant of the glyph to be used, for a font that has several glyphs for one character. It also allows to define the height of a line.