I was reading about difference between two css properties display:none
and visibility:hidden
and encountered DOM reflow term.
The statement was
display: none
causes DOM reflow where isvisibility: hidden
doesn't.
So my question is:
What is DOM reflow and how it works?
A reflow computes the layout of the page. A reflow on an element recomputes the dimensions and position of the element, and it also triggers further reflows on that element’s children, ancestors and elements that appear after it in the DOM. Then it calls a final repaint. Reflowing is very expensive, but unfortunately it can be triggered easily.
Reflow occurs when you:
- insert, remove or update an element in the DOM
- modify content on the page, e.g. the text in an input box
- move a DOM element
- animate a DOM element
- take measurements of an element such as offsetHeight or getComputedStyle
- change a CSS style
- change the className of an element
- add or remove a stylesheet
- resize the window
- scroll
For more information, please refer here: Repaints and Reflows: Manipulating the DOM responsibly
Reflow is the name of the web browser process for re-calculating the positions and geometries of elements in the document, for the purpose of re-rendering part or all of the document.
https://developers.google.com/speed/articles/reflow
display:none
hide the div
as if the div
is not rendered whereas visibility:hidden
only hides but the space is still occupied
It means, that if you will set dinamically display: none;
, your browser will recalculate positions of DOM elements, if visisbility: hidden; - not. Think, it because visibility: hidden;
does not change element sizes in dom.
来源:https://stackoverflow.com/questions/27637184/what-is-dom-reflow