Document: execCommand() method

Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

When an HTML document has been switched to designMode, its document object exposes an execCommand method to run commands that manipulate the current editable region, such as form inputs or contentEditable elements.

Most commands affect the document's selection (bold, italics, etc.), while others insert new elements (adding a link), or affect an entire line (indenting). When using contentEditable, execCommand() affects the currently active editable element.

The Clipboard API can be used instead of execCommand in many cases, but execCommand is still sometimes useful. In particular, the Clipboard API doesn't replace the insertText command, which you can use to programmatically replace text at the cursor while preserving the undo buffer (edit history) in plain textarea and input elements.