Clipboard API

The system clipboard is a data buffer belonging to the operating system hosting the browser, which is used for short-term data storage and/or data transfers between documents or applications. It is usually implemented as an anonymous, temporary data buffer, sometimes called the paste buffer, that can be accessed from most or all programs within the environment via defined programming interfaces.

The Clipboard API allows users to programmatically read and write text and other kinds of data to and from the system clipboard in secure contexts, provided the user has met the criteria outlined in the Security considerations.

Events are fired as the result of cut, copy, and paste operations modifying the clipboard. The events have a default action, for example the copy action copies the current selection to the system clipboard by default. The default action can be overridden by the event handler — see each of the events for more information.

Clipboard Secure context

Provides an interface for reading and writing text and data to or from the system clipboard. The specification refers to this as the 'Async Clipboard API'.

ClipboardEvent

Represents events providing information related to modification of the clipboard, that is cut, copy, and paste events. The specification refers to this as the 'Clipboard Event API'.

ClipboardItem Secure context

Represents a single item format, used when reading or writing data.

The Clipboard API extends the following APIs, adding the listed features.

Navigator.clipboard Read only Secure context

Returns a Clipboard object that provides read and write access to the system clipboard.

Element copy event

An event fired whenever the user initiates a copy action.

Element cut event

An event fired whenever the user initiates a cut action.

Element paste event

An event fired whenever the user initiates a paste action.

The Clipboard API allows users to programmatically read and write text and other kinds of data to and from the system clipboard in secure contexts.

The specification requires that a user has recently interacted with the page in order to read from the clipboard (transient user activation is required). If the read operation is caused by user interaction with a browser or OS "paste element" (such as a context menu), the browser is expected to prompt the user for acknowledgement. For writing to the clipboard the specification expects that the page has been granted the Permissions API clipboard-write permission, and the browser may also require transient user activation. Browsers may place additional restrictions over use of the methods to access the clipboard.

Browser implementations have diverged from the specification. The differences are captured in the Browser compatibility section and the current state is summarized below:

Chromium browsers:

• Reading requires the Permissions API clipboard-read permission be granted. Transient activation is not required.
• Writing requires either the clipboard-read permission or transient activation. If the permission is granted, it persists, and further transient activation is not required.
• The HTTP Permissions-Policy permissions clipboard-read and clipboard-write must be allowed for <iframe> elements that access the clipboard.
• No persistent paste-prompt is displayed when a read operation is caused by a browser or OS "paste element".

Firefox & Safari:

• Reading and writing require transient activation.
• The paste-prompt is suppressed if reading same-origin clipboard content, but not cross-origin content.
• The clipboard-read and clipboard-write permissions are not supported (and not planned to be supported) by Firefox or Safari.

Firefox Web Extensions:

• Reading text is only available for extensions with the Web Extension clipboardRead permission. With this permission the extension does not require transient activation or a paste prompt.
• Writing text is available in secure context and with transient activation. With the Web Extension clipboardWrite permission transient activation is not required.

The system clipboard is accessed through the Navigator.clipboard global.

This snippet fetches the text from the clipboard and appends it to the first element found with the class editor. Since readText() (and read(), for that matter) returns an empty string if the clipboard isn't text, this code is safe.

navigator.clipboard
  .readText()
  .then(
    (clipText) => (document.querySelector(".editor").innerText += clipText),
  );

• Image support for Async Clipboard article