InputEvent：isComposing 属性
Baseline
2023
Newly available
Since March 2023, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.
InputEvent.isComposing 只读属性返回一个布尔值，表示事件是否是在 compositionstart 之后且在 compositionend 之前触发的。