Question: i wonder if there's a difference between 
1.) 10,000 tablerow which is visible
2.) 10,000 tablerow which is hidden using display:none

what i want to know is that. if all 10,000 row is visible on the page, could it cause the page scrolling to lag?

but if i hide for example the 9000 of them. could this reduce the lagging? Thanks guys.

Answer: 
In general `display: none;` will save the browser some work.

The browser will start by parsing your HTML and building the so called DOM (document object model), when all the CSS is received it will go on and build the CSSOM (CSS object model). Those two combined will give the render tree.

With the render tree in hand the browser will perform a layout step (deciding where each element goes on the screen and how big it will be) and then paint the page on the screen.

When combining DOM and CSSOM to become the render tree, however, the browser will discard all subtrees that are `display: none;` and thus, have less work to do in the layout and paint step.
Great question! It is **not** too broad, it is **not discussed enough**.
I'm in the middle of researching this based on a lazy-loading issue I'm having and cross-referencing other websites like Twitter and Reddit feeds.

Lighthouse flags pages with DOM trees that:

* Have more than 1,500 nodes total.
* Have a depth greater than 32 nodes.
* Have a parent node with more than 60 child nodes.

For example I see that Reddit scores a dismal **26**.  

"Avoid an excessive DOM size 1,456 elements" is included as a recommended action.

Reddit.com: Lighthouse says:

> 
> A large DOM will increase memory usage, cause longer style
> calculations, and produce costly layout reflows. Learn more. React
> Consider using a “windowing” library like `react-window` to minimize
> the number of DOM nodes created if you are rendering many repeated
> elements on the page. Learn more. Also, minimize unnecessary re-renders
> using shouldComponentUpdate, PureComponent, or React.memo and skip
> effects only until certain dependencies have changed if you are using
> the Effect hook to improve runtime performance.
> 
> 
> 

<https://web.dev/dom-size/#how-to-optimize-the-dom-size>