固定定位是绝对定位的一种特殊情况，即他的包含框永远都是视口。

Fixed positioning is a subcategory of absolute positioning. The only difference is that for a fixed positioned box, the containing block is established by the viewport.

youdao

底部配有静音万向轮4个，其中两个带有刹车，能起到固定定位，推拉灵活；

The bottom has 4 silent universal wheels, two of which havebrakes, can play a fixedlocation, push and pull flexibly;

youdao

底部配有静音万向轮4个，其中两个带有刹车，能起到固定定位，推拉灵活；

The bottom has 4 silent universal wheels, two of which havebrakes, can play a fixedlocation, push and pull flexibly;

youdao