@alifd/overlay/demo/scroll-position.md

overlay base component

---
title: 弹层滚动自动更新位置
order: 7
---

遇到有 overflow 滚动的弹窗，会自动监听滚动实时弹窗计算位置。触发器消失会自动隐藏

```jsx
import { useState } from 'react';
import Overlay from '@alifd/overlay';

const { Popup } = Overlay;
const style = {
  width: 500,
  height: 100,
  padding: 10,
  background: '#fff',
  borderRadius: 2,
  boxShadow: '2px 2px 20px rgba(0, 0, 0, 0.15)',
};

const App = () => {
  const [position, setPosition] = useState({});
  const [position2, setPosition2] = useState({});

  return (
    <div
      style={{
        position: 'relative',
        height: 150,
        padding: 50,
        border: '1px solid #eee',
        overflow: 'auto',
      }}
    >
      <Popup
        overlay={
          <div style={style}>
            父容器有滚动条，弹窗top自动跟随变化来保持位置不变: {JSON.stringify(position)}
          </div>
        }
        placement="bl"
        onPosition={({ style }) => {
          setPosition(style);
        }}
      >
        <button style={{ marginTop: 10 }}>Open1</button>
      </Popup>
      <br />
      <Popup
        overlay={
          <div style={style}>
            父容器有滚动条，弹窗top自动跟随变化来保持位置不变: {JSON.stringify(position2)}
          </div>
        }
        placement="bl"
        onPosition={({ style }) => {
          setPosition2(style);
        }}
      >
        <button style={{ marginTop: 120 }}>Open2</button>
      </Popup>
      <div style={{ height: 300, width: 1200 }} />
    </div>
  );
};

ReactDOM.render(<App />, mountNode);
```