This chapter describes the DOM Event Model. The Event interface itself is described, as well as the interfaces for event registration on nodes in the DOM, and event listeners, and several longer examples that show how the various event interfaces relate to one another.
The actual value of a CSS property is the used value after all approximations have been applied. For example, a user agent may only be able to render borders with a integer pixel value and may be forced to approximate the computed width of the border.
Browsers use the DOCTYPE declaration to choose whether to show the document using a mode that is more compatible with Web standards or with old browser bugs. Using a correct and modern DOCTYPE declaration at the start of your HTML will improve browser standards compliance.
One of the most common style changes made to lists is a change in the indentation distance—that is, how far the list items are pushed over to the right. This often leads to frustration, because what works in one browser often doesn't have the same effect in another. For example, if you declare that lists have no left margin, they move over in Internet Explorer, but sit stubbornly in place in Gecko-based browsers.This article will help you understand the problems that can occur and how to avoid them.
The summary of every CSS property definition says whether that property is inherited by default ("Inherited: Yes") or not inherited by default ("Inherited: no"). This controls what happens when no value is specified for a property on an element.
Shorthand properties are CSS properties that let you set the values of several other CSS properties simultaneously. Using a shorthand property, a Web developer can write more concise and often more readable style sheets, saving time and energy.
The used value of any CSS property is the final value of that property after all calculations have been performed. For some properties, used values can be retrieved by calling window.getComputedStyle. Dimensions (e.g., width, line-height) are all in pixels, shorthand properties (e.g., background) are consistent with their component properties (e.g., background-color, display) and consistent with position and float, and every CSS property has a value.
This section provides a brief conceptual introduction to the DOM: what it is, how it provides structure for HTML and XML documents, how you can access it, and how this API presents the reference information and examples.
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 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 16.7ms.