1.Remove all borders.
2.Use clip to indicate that no part of the element should be shown.
3.Make the height and width of the element 1px.
4.Negate the elements height and width using margin: -1px.
5.Hide the element's overflow.
6.Remove all padding.
7.Position the element absolutely so that it does not take up space in the DOM.

这里有一部分离屏渲染了离屏渲染