对应文:CSS Flexible Box Layout

flex 常见值效果展示

默认值 flex: initial 相当于 flex: 0 1 auto

item 1
item 2 flex initial
item 3

flex: auto 相当于 flex:1 1 auto

item 1
item 2 has flex property
item 3

flex: none 相当于 flex: 0 0 auto;

item 1
item 2 has flex property,no shrink
item 3

flex: 2 相当于 flex: 2 1 0

item 1
item 2 has flex property
item 3