While most CSS features are defined by the CSS Working Group and either included in CSS Level 2.1, or individual CSS Modules, there are a surprising number squirrelled away in various other specifications. These may or may not have been worked on in conjunction with the CSS WG, but as many probably get overlooked, I thought I’d list them in a blog post so that I can find them later. How many did you know about?
The resource-priority property specifies the download priority of the resource associated with the element (such as the image source or background image.) This includes lazy loading, postponing, or regular loading of the resource.
An Input Method Editor is commonly used for East Asian (CJK) languages to assist typing the specified language with a latin keyboard. It can also be used for other languages, such as to assist typing diacritics. When typing, an IME window pops up allowing the user to select from suggested matches.
The various imeproperties specify the size, positioning, and behaviour of the IME window.
Note: The ime-mode property exists in CSS Basic UI Level 3, but included for completeness as it is part of the ime shorthand.
The :fullscreen pseudo class and ::backdrop pseudo element allows you to style an element and its backdrop (the layer behind the fullscreen element, but on top of the rest of the elements behind it) when in fullscreen mode.
Note: WebKit, Blink, and Gecko browsers support :full-screen rather than the standardised :fullscreen. They each require their vendor prefixes: -webkit- (Chrome, Opera, and Safari), and -moz (Firefox).
The view-mode media feature can be used with Media Queries to specify how a web site or app is styled when in different visual presentations. For example when it is windowed (think typical desktop apps such as on Windows or Mac with UI chrome, when not fully maximised), floating (the same as above, but without the chrome, such as Widgets or Gadgets), fullscreen (takes up the full screen without any chrome, such as Windows Metro apps or fullscreen video), maximised(full screen but with browser chrome, such as a maximised Windows desktop app), or minimised(when it is minimised but there is still some UI showing, such as a Windows Metro live tile, or “living icon”.)
Note: Opera version based on Presto supported the view-modemedia feature. Support was lost when it switched to the Blink rendering engine in version 15.
For SVG properties, I’ve removed any that have been moved into a spec produced by the SVG and CSS Working Group (FX task force) to define how they work in both SVG and HTML/XML, such as Masks, Filters and so on. For subsequent SVG versions I’ve only included the new properties unique to that version.
Most of these properties only work in SVG, but a number have since been made to work in HTML/XML in certain browsers.
For support information for SVG properties, I’ve only tested support by checking official documentation, and for the presence of the property in that browser’s developer tool. There are too many to check thoroughly at this time.
Note: the display-align, line-increment, solid-color, solid-opacity, viewport-fill, and viewport-fill-opacity properties are supported in Presto versions of Opera. They were dropped when switching to the Blink rendering engine.
Notes: The table-baseline property is not actually defined in the MathML for CSS profile spec, but it is referenced in the default CSS style sheet, and is not mentioned in any other W3C specification. Opera previously supported this property until it was dropped when it switched to the Blink rendering engine.