js: 监听键盘按键事件KeyboardEvent

文档

• https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent

事件类型

• keydown
• keypress
• keyup

属性	类型	windows	Mac OS
altKey	Boolean	Alt	Option、⌥
ctrlKey	Boolean	Ctrl	control、^
shiftKey	Boolean	shift	shift
metaKey	Boolean	-	Command、⌘
key	String	-	-
keyCode (Deprecated)	String	-	-

代码示例

  function eventHandler(event) {
    console.log(event);

    let data = {
      code: event.code,
      key: event.key,
      keyCode: event.keyCode,
      altKey: event.altKey,
      shiftKey: event.shiftKey,
      ctrlKey: event.ctrlKey,
      metaKey: event.metaKey,
    };

    let list = [];
    for (let [key, value] of Object.entries(data)) {
      list.push(`
${key}: ${value}
`);
    }

    document.querySelector("#text").innerHTML = list.join("");
  }

  document.addEventListener("keydown", this.eventHandler.bind(this));

在线体验：https://github.com/mouday/front-end-demo/EventListener-keydown.html