js控制浏览器全屏

ie是否可用不明确，其他浏览器可用

取消全屏不同浏览器方法不同，有的是--cancelFullScreen ，有的是--exitFullScreen，为确保起作用，两种方法都加上了

function fullScreen() {
    var el = document.documentElement;
    var rfs = el.requestFullScreen || el.webkitRequestFullScreen || 
        el.mozRequestFullScreen || el.msRequestFullScreen || el.oRequestFullscreen;
    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}");
        }
    }
}
function exitFullScreen() {
    // 判断各种浏览器，找到正确的方法
    var cfs = document.exitFullScreen || document.cancelFullScreen ||//W3C
        document.mozCancelFullScreen || document.mozExitFullScreen ||  //FireFox
        document.webkitCancelFullScreen ||document.webkitExitFullScreen||  //Chrome等
        document.msExitFullScreen; //IE11
    if (typeof cfs != "undefined" && cfs) {
        cfs.call(document);
    }
    else if (typeof window.ActiveXObject !== "undefined") {//for Internet Explorer
        var wscript = new ActiveXObject("WScript.Shell");
        if (wscript !== null) {
            wscript.SendKeys("{F11}");
          wscript.SendKeys("{ESC}");
        }
    }
}