|CSS Flexible Box Layout|
CSS Flexible Box Layout
|Status||Candidate Recommendation (CR)|
|Year started||23 July 2009|
|Latest version||Level 1|
November 9, 2018
|Preview version||Working Draft|
March 25, 2021
|Committee||CSS Working Group|
CSS Flexible Box Layout, commonly known as Flexbox, is a CSS 3 web layout model. It is in the W3C's candidate recommendation (CR) stage. The flex layout allows responsive elements within a container to be automatically arranged depending on viewport (device screen) size.
|Cascading Style Sheets|
Most web pages are written in a combination of HTML (Hypertext Markup Language) and CSS (Cascading Style Sheets). In short, HTML specifies the content and logical structure of the page, while the CSS specifies how it looks: its colors, fonts, formatting, layout, and styling.
CSS flex-box layout is a particular way to specify the layout of HTML pages.
One of the most defining features of the flex layout is its ability to form-fit, based on its viewing environment. Flex boxes can adjust in size—either decreasing, to avoid unnecessarily monopolizing space, or increasing to make room for contents to fit within its boundaries. Moreover, the flex layout is less restrictive in terms of content flow than that of other CSS layout models, which are generally uni-directional. The flex directional flow can be specified rightwards, leftwards, upwards, or downwards. Individual items within a flex container may also be automatically rearranged to suit the available layout space.
CSS 3 modules included solutions akin to this, like flexbox and grid.
As of December 2022[update], 99.68% of installed browsers (99.59% of desktop browsers and 100% of mobile browsers) support CSS Flexible Box Layout.
The following terms are associated with the flexbox layout model.
Designating an element as a flex element requires setting the element's CSS display property to either flex or inline-flex, as follows:
By setting the display to one of the two values above, an element becomes a flex container and its children, flex items. Setting the display to flex makes the container a block-level element, while setting the display to inline-flex makes the container an inline-level element.
One of flexbox's advantages is the ability to easily align items within the container to the center of a page, both vertically and horizontally.
display: flex; align-items: center; justify-content: center;