# Overflow

Decides what happens when content doesn't fit: show, hide or scroll.

## What does `overflow` do?

`overflow` decides what happens when content is too big for its box: show it anyway, hide it, or add scrollbars.

```css
.chat-messages { height: 300px; overflow-y: auto; }   /* scrolls when full */
```

Level: Apprentice · [More CSS terms at this level](https://www.ask-codey.com/glossary/subjects/css/apprentice)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/overflow