flex

The flex CSS property is shorthand for flex-grow, flex-shrink, and flex-basis.

flex: value;

object.style.flex = "value";

<'flex'> = none | [ <'flex-grow'> <'flex-shrink'>? || <'flex-basis'> ]

none

Expands to 0 0 auto.

<'flex-grow'> = <number [0,∞]>

<number [0, ∞]>

An integer or zero or more decimal digits followed by a dot (.) followed by one or more decimal digits. The first character may be preceded by a positive sign (+). The last character may be succeeded by an exponent (e or E) and an integer.

<'flex-shrink'> = <number [0,∞]>

<number [0, ∞]>

An integer or zero or more decimal digits followed by a dot (.) followed by one or more decimal digits. The first character may be preceded by a positive sign (+). The last character may be succeeded by an exponent (e or E) and an integer.

<'flex-basis'> = content | <'width'>

content

Indicates an automatic size based on the flex item's content.

<'width'> = auto | <length-percentage> | min-content | max-content | fit-content( <length-percentage> )

auto

Automatically specified by the user agent.

<length-percentage> = [ <length> | <percentage> ]

<length>

Specifies the length using a number followed by a unit of measurement.

<percentage>

Specifies the percentage using a number followed by a percent sign (%).

min-content

Represents the largest min-content contribution of the items occupying the track.

max-content

Represents the largest max-content contribution of the items occupying the track.

fit-content()

Represents the formula max(minimum, min(limit, max-content)), where minimum represents an auto minimum (which is often, but not always, equal to a min-content minimum), and limit is the track sizing function passed as an argument to fit-content(). This is essentially calculated as the smaller of minmax(auto, max-content) and minmax(auto, limit).

0 1 auto

<!doctype html>
<html>
<head>
    <style>
        #myid {
            display: flex;
        }
        #myid > div {
            background-image: linear-gradient(135deg, white, gray);
        }
        #myid > div:nth-of-type(1) {
            background-image: linear-gradient(135deg, white, yellow);
        }
    </style>
    <script>
        function mouseover(value) {
            var elements = document.getElementById("myid").getElementsByTagName("div");
            for (var i = 0; i < elements.length; ++i) {
                elements[i].style.flex = value;
            }
        }
        function flexGrow(value) {
            document.getElementById("myid").getElementsByTagName("div")[0].style.flexGrow = value;
        }
        function flexShrink(value) {
            document.getElementById("myid").getElementsByTagName("div")[0].style.flexShrink = value;
        }
    </script>
</head>
<body>
    <button onmouseover="mouseover(value)" value="0 1 auto">auto</button>
    <button onmouseover="mouseover(value)" value="0 1 content">content</button>
    <button onmouseover="mouseover(value)" value="0 1 100px">length</button>
    <button onmouseover="mouseover(value)" value="0 1 max-content">max-content</button>
    <button onmouseover="mouseover(value)" value="0 1 min-content">min-content</button>
    <button onmouseover="mouseover(value)" value="0 1 20%">percentage</button>
    <button onmouseover="mouseover(value);flexGrow(2)" value="1 1 auto">flex-grow</button>
    <button onmouseover="mouseover(value);flexShrink(2)" value="0 1 25%">flex-shrink</button>
    <input onmouseover="mouseover(value)" type="button" value="none">
    <div id="myid">
        <div>flex</div>
        <div>flex</div>
        <div>flex</div>
        <div>flex</div>
        <div>flex</div>
    </div>
</body>
</html>

flex-basis

flex-grow

flex-shrink

World Wide Web Consortium (W3C)