截进入全屏

function fullScreen() {

  var el = document.documentElement;

  var rfs = el.requestFullScreen || el.webkitRequestFullScreen || 

      el.mozRequestFullScreen || el.msRequestFullScreen;

  if(typeof rfs != "undefined" && rfs) {

    rfs.call(el);

  } else if(typeof window.ActiveXObject != "undefined") {

    //for IE，这里其实就是模拟了按下键盘的F11，使浏览器全屏

    var wscript = new ActiveXObject("WScript.Shell");

    if(wscript != null) {

        wscript.SendKeys("{F11}");

    }

  }
}

退出全屏幕

function exitFull() {
  // 判断各种浏览器，找到正确的方法
  var exitMethod = document.exitFullscreen || document.mozCancelFullScreen || document.webkitExitFullscreen || document.webkitExitFullscreen; 
  if (exitMethod) {
    exitMethod.call(document);
  }
  else if (typeof window.ActiveXObject !== "undefined") {//for Internet Explorer
    var wscript = new ActiveXObject("WScript.Shell");
    if (wscript !== null) {
      wscript.SendKeys("{F11}");
    }
  }
}