Element: compositionstart event

The compositionstart event is fired when a text composition system such as an input method editor starts a new composition session.

For example, this event could be fired after a user starts entering a Chinese character using a Pinyin IME.

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("compositionstart", (event) => {});

oncompositionstart = (event) => {};

Event type

A CompositionEvent. Inherits from Event.

Event properties

This interface also inherits properties of its parent, UIEvent, and its ancestor — Event.

CompositionEvent.data Read only: Returns the characters generated by the input method that raised the event; its varies depending on the type of event that generated the CompositionEvent object.
CompositionEvent.locale Read only Deprecated: Returns the locale of current input method (for example, the keyboard layout locale if the composition is associated with IME).

Examples

const inputElement = document.querySelector('input[type="text"]');

inputElement.addEventListener("compositionstart", (event) => {
  console.log(`generated characters were: ${event.data}`);
});

Live example

HTML

html

<div class="control">
  <label for="example">
    First select textbox, then to open IME:
    <ul>
      <li>on macOS type <kbd>option</kbd> + <kbd>`</kbd></li>
      <li>on Windows type <kbd>windows</kbd> + <kbd>.</kbd></li>
    </ul>
  </label>
  <input type="text" id="example" name="example" />
</div>

<div class="event-log">
  <label for="eventLog">Event log:</label>
  <textarea
    readonly
    class="event-log-contents"
    rows="8"
    cols="25"
    id="eventLog"></textarea>
  <button class="clear-log">Clear</button>
</div>

body {
  padding: 0.2rem;
  display: grid;
  grid-template-areas: "control log";
}

.control {
  grid-area: control;
}

.event-log {
  grid-area: log;
}

.event-log-contents {
  resize: none;
}

label,
button {
  display: block;
}

input[type="text"] {
  margin: 0.5rem 0;
}

kbd {
  border-radius: 3px;
  padding: 1px 2px 0;
  border: 1px solid black;
}

JavaScript

const inputElement = document.querySelector('input[type="text"]');
const log = document.querySelector(".event-log-contents");
const clearLog = document.querySelector(".clear-log");

clearLog.addEventListener("click", () => {
  log.textContent = "";
});

function handleEvent(event) {
  log.textContent += `${event.type}: ${event.data}\n`;
}

inputElement.addEventListener("compositionstart", handleEvent);
inputElement.addEventListener("compositionupdate", handleEvent);
inputElement.addEventListener("compositionend", handleEvent);

Result

Specifications

Specification
UI Events # event-type-compositionstart

Browser compatibility

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