The data read-only property of the CompositionEvent interface returns the characters generated by the input method that raised the event; its exact nature varies depending on the type of event that generated the CompositionEvent object.

A string representing the event data:

• For compositionstart events, this is the currently selected text that will be replaced by the string being composed. This value doesn't change even if content changes the selection range; rather, it indicates the string that was selected when composition started.
• For compositionupdate, this is the string as it stands currently as editing is ongoing.
• For compositionend events, this is the string as committed to the editor.

• CompositionEvent