A box height

clarify the following questions:

1. when will the left height change?
2. get its height when it changes
3. the right side adjusts to this height

this should be controlled by layout and style

the simplest: a table, has no height, is divided into two columns, and then inserts content in each column, automatically realizing

the whole box height is filled according to the size on the right,
set max-height

learn about flex layout

http://www.ruanyifeng.com/blo.

like my blog space layout, use css flex layout to control it within one screen. Content overflow can be scrolled.
something like this.
places

// main->aside + section
main{display:flex;height:100vh;}
aside{width:200px;// height:100%;}
section{flex:1;height:100%;}