javascript:如何防止默认exitFullscreen事件？

// 获取全屏元素
var fullscreenElement = document.fullscreenElement || document.mozFullScreenElement || document.webkitFullscreenElement;

// 监听fullscreenchange事件
document.addEventListener('fullscreenchange', function(event) {
  // 判断当前是否处于全屏状态
  if (!document.fullscreenElement && !document.mozFullScreenElement && !document.webkitFullscreenElement) {
    // 重新进入全屏状态
    fullscreenElement.requestFullscreen();
  }
});