ant-design/components/affix/index.en-US.md

category	type	title
Components	Navigation	Affix

Make an element sticky to viewport.

When To Use

When user browses a long web page, some content need to stick to the viewport. This is common for menus and actions.

Please note that Affix should not cover other content on the page, especially when the size of the viewport is small.

API

Property	Description	Type	Default
offsetTop	Pixels to offset from top when calculating position of scroll	number	0
offsetBottom	Pixels to offset from bottom when calculating position of scroll	number	-
target	specifies the scrollable area dom node	() => HTMLElement	() => window
onChange	Callback when affix state is changed	Function(affixed)	-

Note: Children of Affix can not be position: absolute, but you can set Affix as position: absolute:

<Affix style={{ position: 'absolute', top: y, left: x}}>
  ...
</Affix>