CSS overflow

TheCSS overflow module properties enable you to handle scrollable overflow in visual media.

Overflow happens when the content in an element box extends past one or more of the box's edges.Scrollable overflow is the content that appears outside the element box for which you might want to add a scrolling mechanism. CSS overflow properties let you control what happens when content overflows an element box, including creating carousels without JavaScript.

Painting effects that overflow the content but do not participate in the CSS box model do not affect layout. This type of overflow is also known as ink overflow. Examples of ink overflows include box shadows, border images, text decoration, overhanging glyphs, and outlines. Ink overflows do not extend the scrollable overflow region.

Overflow in action

Try the following example to see the effects of variousoverflow property values on the content overflow and scrollbars in the adjacent fixed-size box.

The example includes options to change the values for theoverflow-clip-margin andwidth properties, as well as to programmatically scroll the content if the overflow property creates ascroll container. Selectoverflow: clip and see the effect of differentoverflow-clip-margin values. Selectoverflow: hidden oroverflow: scroll to check out the variousScrollLeft andScrollTop slider settings.

<article>  <fieldset>    <legend>Select options:</legend>    <label      ><code>overflow</code>:      <select>        <option>hidden</option>        <option>clip</option>        <option>scroll</option>        <option>auto</option>        <option selected>visible</option>        <option>overlay</option>      </select>    </label>    <label>      <code>overflow-clip-margin</code>:      <input type="number" value="1" min="0" max="10" size="2" />      <code>em</code>    </label>    <label      ><input type="checkbox" /> <code>width</code>:      <code>20em</code> or <code>40em</code></label    >    <fieldset>      <legend>Scroll programmatically:</legend>      <label        >ScrollLeft:        <input type="range" min="0" max="100" value="0"      /></label>      <label        >ScrollTop:        <input type="range" min="0" max="100" value="0"      /></label>    </fieldset>  </fieldset>  <pre>&nbsp;    Oh, Rubber Duckie, you're the one    You make bath time lots of fun    Rubber Duckie, I'm awfully fond of you    Rubber Duckie, joy of joys    When I squeeze you, you make noise    Rubber Duckie, you're my very best friend, it's true    Oh, every day when I make my way to the tubby    I find a little fella who's cute and yellow and chubby    Rub-a-dub-dubby    <a href="#">Rubber Duckie</a>, you're so fine    And I'm lucky that you're mine    Rubber Duckie, I'm awfully fond of you      </pre></article>

article {  display: flex;  gap: 1em;}label {  display: block;  white-space: nowrap;}pre {  border: 2px dashed crimson;  height: 150px;  width: 20em;  margin-bottom: 3em;  overflow-clip-margin: 1em;  text-align: center;}.wide {  width: 40em;}::before {  font-weight: bold;  color: white;  background: crimson;  display: inline-block;  min-width: 50%;  padding: 3px 5px;  box-sizing: border-box;}.hidden {  overflow: hidden hidden;}.hidden::before {  content: "hidden: ";}.clip {  overflow: clip clip;}.clip::before {  content: "clip: ";}.scroll {  overflow: scroll scroll;}.scroll::before {  content: "scroll: ";}.auto {  overflow: auto auto;}.auto::before {  content: "auto: ";}.overlay {  overflow: clip clip;  overflow: overlay overlay;}.overlay::before {  content: "overlay (or clip if not supported): ";}.visible {  overflow: visible visible;}.visible::before {  content: "visible: ";}article:not(:has(pre.clip)) > fieldset > label:nth-of-type(2),article:not(:has(pre.hidden, pre.scroll, pre.auto, pre.overlay))  fieldset  fieldset {  opacity: 20%;  pointer-events: none;}

const pre = document.querySelector("pre");const val = document.getElementById("overflowValue");const check = document.getElementById("wide");const ocm = document.getElementById("ocm");const scrollL = document.getElementById("scrollL");const scrollT = document.getElementById("scrollT");val.addEventListener("change", () => {  if (pre.classList.contains("wide")) {    pre.className = `wide ${val.value}`;  } else {    pre.className = `${val.value}`;  }  scrollExample();  clipMargin();});wide.addEventListener("change", () => {  pre.classList.toggle("wide");  scrollExample();});ocm.addEventListener("change", () => {  clipMargin();});scrollL.addEventListener("change", () => {  scrollExample();});scrollT.addEventListener("change", () => {  scrollExample();});function scrollExample() {  pre.scrollTo({    top: scrollT.value,    left: scrollL.value * 2,    behavior: "smooth",  });}function clipMargin() {  pre.style.overflowClipMargin = `${ocm.value}em`;}

A link is included in the content box above to demonstrate the effects of keyboard focus on overflow and scroll behaviors. Try tabbing to the link or programmatically scrolling the content: the content will scroll only if the enumerated<overflow> value creates a scroll container.

Reference

Properties

Note:The CSS Overflow Module Level 4 introduces theblock-ellipsis,continue,max-lines,overflow-clip-margin-block,overflow-clip-margin-block-end,overflow-clip-margin-block-start,overflow-clip-margin-bottom,overflow-clip-margin-inline,overflow-clip-margin-inline-end,overflow-clip-margin-inline-start,overflow-clip-margin-left,overflow-clip-margin-right, andoverflow-clip-margin-top properties. These have not yet been implemented.

Selectors and pseudo-elements

Data types

<overflow> enumerated values

Guides

Learn: Overflowing content: Learn what overflow is and how to manage it.
Creating CSS carousels: Create pure-CSS carousel UI features using scroll buttons, scroll markers, and generated columns.
Creating a named scroll progress timeline animation: The CSS scroll timelinescroll-timeline-name andscroll-timeline-axis properties, along with thescroll-timeline shorthand, create animations tied to the scroll offset of a scroll container.