文本合成系统如 input method editor(即输入法编辑器)开始新的输入合成时会触发 compositionstart
事件。
例如,当用户使用拼音输入法开始输入汉字时,这个事件就会被触发。
Bubbles | Yes | |
Cancelable | Yes | |
Interface | CompositionEvent |
|
Event handler property |
|
示例
const inputElement = document.querySelector('input[type="text"]'); inputElement.addEventListener('compositionstart', (event) => { console.log(`generated characters were: ${event.data}`); });
动态演示
HTML
<div class="control"> <label for="name">On macOS, click in the textbox below,<br> then type <kbd>option</kbd> + <kbd>`</kbd>, then <kbd>a</kbd>:</label> <input type="text" id="example" name="example"> </div> <div class="event-log"> <label>Event log:</label> <textarea readonly class="event-log-contents" rows="8" cols="25"></textarea> <button class="clear-log">Clear</button> </div>
CSS
body { padding: .2rem; display: grid; grid-template-areas: "control log"; } .control { grid-area: control; } .event-log { grid-area: log; } .event-log-contents { resize: none; } label, button { display: block; } input[type="text"] { margin: .5rem 0; } kbd { border-radius: 3px; padding: 1px 2px 0; border: 1px solid black; }
JS
const inputElement = document.querySelector('input[type="text"]'); const log = document.querySelector('.event-log-contents'); const clearLog = document.querySelector('.clear-log'); clearLog.addEventListener('click', () => { log.textContent = ''; }); function handleEvent(event) { log.textContent = log.textContent + `${event.type}: ${event.data}\n`; } inputElement.addEventListener('compositionstart', handleEvent); inputElement.addEventListener('compositionupdate', handleEvent); inputElement.addEventListener('compositionend', handleEvent);
结果
规范
规范 | 状态 |
---|---|
UI Events | Working Draft |
浏览器兼容性
BCD tables only load in the browser
参见
- 相关事件:
compositionend
,compositionupdate
.