ant-design/components/affix/demo/target.md

order	title
2	zh-CN en-US 滚动容器 Container to scroll.

zh-CN

用 target 设置 Affix 需要监听其滚动事件的元素，默认为 window。

en-US

Set a target for 'Affix', which is listen to scroll event of target element (default is window).

import { Affix, Button } from 'antd';

class Demo extends React.Component {
  render() {
    return (
      <div
        className="scrollable-container"
        ref={node => {
          this.container = node;
        }}
      >
        <div className="background">
          <Affix target={() => this.container}>
            <Button type="primary">Fixed at the top of container</Button>
          </Affix>
        </div>
      </div>
    );
  }
}

ReactDOM.render(<Demo />, mountNode);