Explication détaillée des méthodes d'implémentation JavaScript en plein écran et sortie du plein écran

window.isflsgrn = false;//ie11以下是否进入全屏标志，true为全屏状态，false为非全屏状态
      window.ieIsfSceen = false;//ie11是否进入全屏标志，true为全屏状态，false为非全屏状态
      //跨浏览器返回当前 document 是否进入了可以请求全屏模式的状态
      function fullscreenEnable(){
        var isFullscreen = document.fullscreenEnabled ||
        window.fullScreen ||
        document.mozFullscreenEnabled ||
        document.webkitIsFullScreen;
        return isFullscreen;
      }
      //全屏
      var fScreen = function(){
        var docElm = document.documentElement;
        if (docElm.requestFullscreen) {
          docElm.requestFullscreen();
        }
        else if (docElm.msRequestFullscreen) {
          docElm.msRequestFullscreen();
          ieIsfSceen = true;
        }
        else if (docElm.mozRequestFullScreen) {
          docElm.mozRequestFullScreen();
        }
        else if (docElm.webkitRequestFullScreen) {
          docElm.webkitRequestFullScreen();
        }else {//对不支持全屏API浏览器的处理，隐藏不需要显示的元素
          window.parent.hideTopBottom();
          isflsgrn = true;
          $("#fsbutton").text("退出全屏");
        }
      }
      //退出全屏
      var cfScreen = function(){
        if (document.exitFullscreen) {
          document.exitFullscreen();
        }
        else if (document.msExitFullscreen) {
          document.msExitFullscreen();
        }
        else if (document.mozCancelFullScreen) {
          document.mozCancelFullScreen();
        }
        else if (document.webkitCancelFullScreen) {
          document.webkitCancelFullScreen();
        }else {
          window.parent.showTopBottom();
          isflsgrn = false;
          $("#fsbutton").text("全屏");
        }
      }
      //全屏按钮点击事件
      $("#fsbutton").click(function(){
        var isfScreen = fullscreenEnable();
        if(!isfScreen && isflsgrn == false){
          if (ieIsfSceen == true) {
            document.msExitFullscreen();
            ieIsfSceen = false;
            return;
          }
          fScreen();
        }else{
          cfScreen();
        }
      })
      //键盘操作
      $(document).keydown(function (event) {
        if(event.keyCode == 27 && ieIsfSceen == true){
          ieIsfSceen = false;
        }
      });
      //监听状态变化
      if (window.addEventListener) {
        document.addEventListener('fullscreenchange', function(){ 
          if($("#fsbutton").text() == "全屏"){
            $("#fsbutton").text("退出全屏"); 
          }else{
            $("#fsbutton").text("全屏");
          }
        });
        document.addEventListener('webkitfullscreenchange', function(){ 
          if($("#fsbutton").text() == "全屏"){
            $("#fsbutton").text("退出全屏"); 
          }else{
            $("#fsbutton").text("全屏");
          }
        });
        document.addEventListener('mozfullscreenchange', function(){ 
          if($("#fsbutton").text() == "全屏"){
            $("#fsbutton").text("退出全屏"); 
          }else{
            $("#fsbutton").text("全屏");
          }
        });
        document.addEventListener('MSFullscreenChange', function(){ 
          if($("#fsbutton").text() == "全屏"){
            $("#fsbutton").text("退出全屏"); 
          }else{
            $("#fsbutton").text("全屏");
          }
        });
      }