CSS Property flex-basis

The flex-basis property is a property of the Flexible Box Layout.

The flex-basis property sets the initial length of a flexible item before any available space is distributed according to the flex factors.

When omitted from the flex shorthand, its specified value is the length zero.

A flex-basis value set to auto sizes the element according to its size property.

Summary

Initial value: auto
Inherited: no
CSS Version: CSS3
JavaScript syntax: object.style.flexBasis="20px"
Animatable: yes

CSS Syntax

flex-basis: number|auto|initial|inherit;

Property Values

number: A length unit or percentage sets the initial length of the flexible item(s)
auto: Default value. The length is equal to the length of the flexible item.
initial: sets to default value
inherit: Inherits this property from its parent element

Browser compatibility


`flex-basis`	Yes	11.0	28.0 (18.0 -moz-)	Yes	Yes

Example

<!DOCTYPE html>
<html>
<head>
<style>
#main {<!--from ww  w . j  a  va  2s  .  co  m-->
    width: 350px;
    height: 100px;
    display: -webkit-flex; /* Safari */
    display: flex;
}

#main div {
    -webkit-flex-grow: 0; /* Safari 6.1+ */
    -webkit-flex-shrink: 0; /* Safari 6.1+ */
    -webkit-flex-basis: 40px; /* Safari 6.1+ */
    flex-grow: 0;
    flex-shrink: 0;
    flex-basis: 20px;
}

#main div:nth-of-type(2) {
    -webkit-flex-basis: 20px; /* Safari 6.1+ */
    flex-basis: 20px;
}
</style>
</head>
<body>

<div id="main">
  <div style="background-color:red;"></div>
  <div style="background-color:blue;"></div>
  <div style="background-color:yellow;"></div>
  <div style="background-color:pink;"></div>
  <div style="background-color:grey;"></div>
</div>

</body>
</html>

Click to view the demo

Example 2

<!DOCTYPE html>
<html class=''>
<style>
.flex-container {<!--from w  ww.j av a2  s  .  c o m-->
  padding: 0;
  margin: 0;
  list-style: none;
  
  -ms-box-orient: horizontal;
  display: -webkit-box;
  display: -moz-box;
  display: -ms-flexbox;
  display: -moz-flex;
  display: -webkit-flex;
  display: flex;
}

.flex-item {
  background: red;
  padding: 10px;
  border: 1px solid black;
  color: white;
  text-align: center;
}

.flex1 { flex: 1 1 20em; }
.flex2 { flex: 2 2 20em; } 
</style>
</head>
<body>
<ul class="flex-container">
  <li class="flex-item flex1">1</li>
  <li class="flex-item flex2">2</li>
</ul>
</body></html>

Click to view the demo