Element: compositionstart event

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Thuộc tính compositionstart 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 Input method editor.

Cú pháp

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

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

oncompositionstart = (event) => { }

Event type

Một CompositionEvent. Inherits from UIEvent and 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).

Ví dụ

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">
    Focus the text-input control, then open your IME and begin typing.
  </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

Đặc tả kỹ thuật

Specification
UI Events # event-type-compositionstart

Trình duyệt hỗ trợ

Xem thêm

Related events: compositionend, compositionupdate.

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