js实现浏览器窗口全屏和退出全屏的功能，市面上主流浏览器如：谷歌、火狐、360等都是兼容的，不过IE低版本有点瑕疵（全屏状态下仍有底部的状态栏）。
这个demo基本是够了，直接复制下面的源码另存为html文件看效果吧。
<!DOCTYPE html>
<html>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>js全屏和退出全屏代码</title>
<body>
<!-- requestFullScreen(document.documentElement): 整个网页进入全屏
requestFullScreen(document.getElementById("video-box")): 指定某块区域全屏
-->
<button onclick="requestFullScreen(document.documentElement)">全屏显示</button>
<button onclick="exitFull()">退出全屏</button>
</body>
<script type="text/javascript">
function requestFullScreen(element) {
// 判断各种浏览器，找到正确的方法
var requestMethod = element.requestFullScreen || //W3C
element.webkitRequestFullScreen || //Chrome等
element.mozRequestFullScreen || //FireFox
element.msRequestFullScreen; //IE11
if (requestMethod) {
requestMethod.call(element);
}
else if (typeof window.ActiveXObject !== "undefined") {//for Internet Explorer
var wscript = new ActiveXObject("WScript.Shell");
if (wscript !== null) {
wscript.SendKeys("{F11}");
}
}
}
//退出全屏 判断浏览器种类
function exitFull() {
// 判断各种浏览器，找到正确的方法
var exitMethod = document.exitFullscreen || //W3C
document.mozCancelFullScreen || //Chrome等
document.webkitExitFullscreen || //FireFox
document.webkitExitFullscreen; //IE11
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}");
}
}
}
</script>
</html>