1. visualviewport api

2. visualviewport api: height

3. visualviewport api: offsetleft

4. visualviewport api: offsettop

5. visualviewport api: pageleft

6. visualviewport api: pagetop

7. visualviewport api: `resize` event

8. visualviewport api: scale

9. visualviewport api: `scrollend` event

10. visualviewport api: `scroll` event

11. visualviewport api: width

12. window api: visualviewport