Performance differences between visibility:hidden and display:none

Question

I want to simplify things in my jQuery Backbone.js web application. One such simplification is the behavior of my menu and dialog widgets.

Previously I created the div boxes of my menus at start and hid them using display: none; opacity:0;. When I needed a menu, I changed its style to display:block then used the jQuery ui position utility to position the div box (since elements with display:none cannot be positioned) and when it was done, finally changed its style to opacity:1.

Now I want to just hide them with visibility:hidden, and when I need one, I use the position utility and then change the style to visibility:visible. When I begin using this new approach, I will have around 10 div boxes throughout the web application session that are hidden but occupy space, in contrast to the previous div boxes hidden with display:none.

What are the implications of my new approach? Does it effect browser performance in any regard?

Solution 1

I'm not aware of any performance difference between display:none and visibility:hidden - even if there is, for as little as 10 elements it will be completely negligible. Your main concern should be, as you say, whether you want the elements to remain within the document flow, in which case visibility is a better option as it maintains the box model of the element.

Solution 2

display:none; elements are not in the render tree all, so they will perform better at face value.

I doubt you will have any real visible performance problems from this though. If you need opacity: 0 or visibility: hidden because of their functionality, then just use them. If you don't need the functionality, then use display: none;

Solution 3

If you are toggling between visible and invisible states via javascript then visibility:hidden should be the better performer. Seeing as it always takes up the same amount of space in both visible and hidden states it won't cause a reflow of the elements below it every time you make it appear of disappear. For display:none you are removing it from the flow of the document and then when you set it to display:block you are rerendering it and pushing everything below that element down, essentially laying all that stuff out again.

But if you are doing something like toggling visible states on button presses then you really should be using what suits your needs rather than what performs better, as the performance differences are negligible in such cases. When you are animating with the dom at around 20 times per second THEN you can worry about the performance of visibility:hidden vs display:none.

Solution 4

visibility: hidden does not cause a re-flow on the document, while display: none does.

display: none: The HTML engine will completely ignore the element and its children. The engine will not ignore elements marked with visibility: hidden, it will do all the calculations to the element and its children, the exception is that the element will not be rendered to the viewport.

If the values for position and dimensions properties are needed then visibility: hidden have to be used and you have to handle the white space in the viewport, usually by wrapping that element inside another one with 0 width and height and 'overflow: hidden'.

display:none will remove the element from the document's normal flow and set the values for position/height/width to 0 on the element and its children. When the elements display property is changed to other value than none, it triggers a complete document re-flow, which can be a problem for big documents - and sometimes not-so-big documents being rendered on hardware with limited capabilities.

display: none is the natural and logical solution to use when hiding elements on the viewport, visibility: hidden should be used as a fallback, where/when needed.

EDIT: As pointed by @Juan, display: none is the choice to go when what you need is to add many elements to the DOM tree. visibility: hidden will trigger a re-flow for each element added to the tree, while display: none will not.

Solution 5

Well, the main performance difference between display: block and visibility: hidden is that if you have a list of, say, 100000 elements, the visibility: hidden won't save you from DOM hanging because it doesn't remove elements from DOM. visibility: hidden acts like opacity: 0 + pointer-events: none. display: none acts like Element.remove().

Live example: https://jsfiddle.net/u2dou58r/10/

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Comments

[chrisfrancis27]

+1 - very interesting! Do you know which browsers have this render tree optimisation?

[Esailija]

@ChrisFrancis I want to say all but you can never know about IE :D

[Esailija]

Just because an element is in DOM hierarchy doesn't mean anything in terms of performance. It depends on how costly it is to render that element and its children on the screen, which can vary arbitrarily.

[Marcelo De Zen]

Even IE ignores the element if it has "display: none".

[Dan Abramov]

Although it may perform better the first time, if you're toggling display fast, you're asking for trouble. Check out the other answers.

[Stephen M. Harris]

I'd upvote this if you provided sources. I know that display:none causes a reflow whereas visibility:hidden does not ... so intuitively I think you are dead-on. But good answers on SO link to official documentation or deeper explanations; I don't have enough background on this subject to +1 this without sources.

[Francisc0]

this article by Nicole Sullivan talks about it. She's generally considered a CSS expert and helped to build CSSLint. Don't know if this qualifies as a good source but I certainly trust her opinion stubbornella.org/content/2009/03/27/…

[Juan Lanus]

This is the real issue with display:none vs. visibility:hidden. If you are adding a lot of elements to a DOM, and you add them hidden, then you'll provoke a reflow for each one. On the other hand, you can add as many elements as you want with display:none and show them all at once provoking a single reflow. The performance taxing action is the the reflow.

[FlavorScape]

in cases where you have hundreds of elements, such as a tiled map or game, I always remove display attributes in reverse-dom order to prevent reflows on the container!

[Thor Lancaster]

For one of my pages with 3D CSS effects and several thousand elements in the DOM, toggling "display" on a large container element caused a lag of almost 500ms on slower mobile devices. Changing the CSS to instead toggle "visibility" eliminated the lag entirely.

[Ayyappa Gollu]

@andywhyisit from this resource it says that changine display to None doesn't cause reflow .. but changing visibility to hidden cause 1x reflow in browsers. developers.google.com/speed/docs/insights/browser-reflow for me your answer seems correct. but resoursce provided aboove contradicts it. so which one is right ?

[gaurav5430]

both of them are in the DOM tree, but display:none wouldn't be in the render tree

[gaurav5430]

why would display:none perform better at face value? it is not in the render tree, but as soon as you toggle it to display: block or other, it will become a part of the render tree and lead to re layout, while visibility change (theoretically) should not lead to trigger layout

[gaurav5430]

@juanlanus are you suggesting that adding a lot of elements with visibility hidden and changing the visibility to visible for each one of them would provoke a reflow of the document / parent element? OR are you suggesting that each of these elements would reflow every time there is a reflow triggered on the doc due to some reason, as they are part of the render tree?

[gaurav5430]

is that because visibility: hidden elements are still aprt of the layout step bit not display:none

[Marcelo De Zen]

@gaurav5430 a reflow is triggered when a new element is inserted into the DOM. However, if the parent element has display:none, the reflow is not triggered when a new element is added. Visibility:hidden will still trigger a reflow.

[gaurav5430]

why though, the element is already in the DOM / render tree, we only toggle the visibility from none to visible

[Limbo]

@gaurav5430 well, technically, yes. But it's not quite correct to say that display: none elements are not part of the layout, because they can be still reached through JS DOM methods (like querySelector). Also, they will still affect nth-child CSS pseudo-selectors