如何触发OpenLayers 3全屏事件？

<script src="https://cdn.jsdelivr.net/npm/ol@3.20.1/dist/ol.js"></script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/ol@3.20.1/dist/ol.css" />

<div id="map" style="width: 100%; height: 400px;"></div>

var map = new ol.Map({
  target: 'map',
  layers: [
    new ol.layer.Tile({
      source: new ol.source.OSM()
    })
  ],
  view: new ol.View({
    center: ol.proj.fromLonLat([0, 0]),
    zoom: 2
  })
});

map.getView().on('change:resolution', function(event) {
  var isFullScreen = map.getView().getResolution() == map.getView().getMinResolution();
  if (isFullScreen) {
    // 在全屏模式下执行的操作
    console.log('进入全屏模式');
  } else {
    // 在退出全屏模式下执行的操作
    console.log('退出全屏模式');
  }
});