HTML5如何监听video的全屏和退出全屏？

监听fullscreenchange事件

document.addEventListener('fullscreenchange', (event) => {  // document.fullscreenElement will point to the element that  // is in fullscreen mode if there is one. If there isn't one,  // the value of the property is null.  if (document.fullscreenElement) {    console.log(`Element: ${document.fullscreenElement.id} entered full-screen mode.`);  } else {    console.log('Leaving full-screen mode.');  }});