The overflow
CSS shorthand property sets the desired behavior when content does not fit in the parent element box (overflows) in the horizontal and/or vertical direction.
Constituent properties
This property is a shorthand for the following CSS properties:
Syntax
/* Keyword values */ overflow: visible; overflow: hidden; overflow: clip; overflow: scroll; overflow: auto; overflow: hidden visible; /* Global values */ overflow: inherit; overflow: initial; overflow: revert; overflow: revert-layer; overflow: unset;
The overflow
property is specified as one or two <overflow>
keyword values. If only one keyword is specified, both overflow-x
and overflow-y
are set to the same value. If two keywords are specified, the first value applies to overflow-x
in the horizontal direction and the second one applies to overflow-y
in the vertical direction.
Values
visible
-
Overflow content is not clipped and may be visible outside the element's padding box. The element box is not a scroll container. This is the default value of the
overflow
property. hidden
-
Overflow content is clipped at the element's padding box. There are no scroll bars, and the clipped content is not visible (i.e., clipped content is hidden), but the content still exists. User agents do not add scroll bars and also do not allow users to view the content outside the clipped region by actions such as dragging on a touch screen or using the scroll wheel on a mouse. The content can be scrolled programmatically (for example, by setting the value of the
scrollLeft
property or thescrollTo()
method), in which case. The element box is a scroll container. clip
-
Overflow content is clipped at the element's overflow clip edge that is defined using the
overflow-clip-margin
property. As a result, content overflows the element's padding box by the<length>
value ofoverflow-clip-margin
or by0px
if not set. Overflow content outside the clipped region is not visible, user agents do not add a scroll bar, and programmatic scrolling is also not supported. No new formatting context is created. To establish a formatting context, useoverflow: clip
along withdisplay: flow-root
. The element box is not a scroll container. scroll
-
Overflow content is clipped at the element's padding box, and overflow content can be scrolled into view using scroll bars. User agents display scroll bars in both horizontal and vertical directions if only one value is set, whether or not any content is overflowing or clipped. The use of this keyword, therefore, can prevent scroll bars from appearing and disappearing as content changes. Printers may still print overflowing content. The element box is a scroll container.
auto
-
Overflow content is clipped at the element's padding box, and overflow content can be scrolled into view. Unlike
scroll
, user agents display scroll bars only if the content is overflowing and hide scroll bars by default. If content fits inside the element's padding box, it looks the same as withvisible
but still establishes a new formatting context. The element box is a scroll container.
Note: The keyword value overlay
is a legacy value alias for auto
. With overlay
, the scroll bars are drawn on top of the content instead of taking up space.
Description
Overflow options include hiding overflowing content, enabling scroll bars to view overflow content or displaying the content flowing out of an element box into the surrounding area, and combinations there of.
The following nuances should be kept in mind while using the various keywords for overflow
:
- Specifying a value other than
visible
(the default) orclip
foroverflow
creates a new block formatting context. This is necessary for technical reasons; if a float intersects with a scrolling element, it would forcibly rewrap the content after each scroll step, leading to a slow scrolling experience. - For an
overflow
setting to create the desired effect, the block-level element must have either a set height (height
ormax-height
) orwhite-space
set tonowrap
. - Setting one axis to
visible
(the default) while setting the other to a different value results invisible
behaving asauto
. - The JavaScript
Element.scrollTop
property may be used to scroll through content in a scroll container, including whenoverflow
is set tohidden
.
Examples
Demonstrating results of various overflow keywords
HTML
<div> <code>visible</code> <p class="visible"> Maya Angelou: "I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel." </p> </div> <div> <code>hidden</code> <p class="hidden"> Maya Angelou: "I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel." </p> </div> <div> <code>clip</code> <p class="clip"> Maya Angelou: "I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel." </p> </div> <div> <code>scroll</code> <p class="scroll"> Maya Angelou: "I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel." </p> </div> <div> <code>auto</code> <p class="auto"> Maya Angelou: "I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel." </p> </div> <div> <code>overlay</code> <p class="overlay"> Maya Angelou: "I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel." </p> </div>
CSS
p.visible { overflow: visible; } p.hidden { overflow: hidden; } p.clip { overflow: clip; overflow-clip-margin: 1em; } p.scroll { overflow: scroll; } p.auto { overflow: auto; } p.overlay { overflow: overlay; }
Accessibility concerns
A scrolling content area cannot be scrolled by a keyboard-only user, with the exception of users on Firefox (which makes the container keyboard focusable by default).
As a developer, to allow non-Firefox keyboard-only users to scroll the container, you will need to give it a tabindex
using tabindex="0"
. Unfortunately, when a screen reader encounters this tab-stop, they will have no context for what it is and their screen reader will likely announce the entirety of its contents. Giving it an appropriate WAI-ARIA role (role="region"
, for example) and an accessible name (via aria-label
or aria-labelledby
) can mitigate this.
See also
overflow-x
,overflow-y
overflow-block
,overflow-clip-margin
,overflow-inline
clip
,display
,text-overflow
,white-space
- CSS overflow
- Keyboard-only scrolling areas on adrianroselli.com (2022)