利用浏览器全屏api实现js全屏

代码如下:
(function () {
 var fullScreenApi = {
  supportsFullScreen : false,
  isFullScreen : function () {
   return false;
  },
  requestFullScreen : function () {},
  cancelFullScreen : function () {},
  fullScreenEventName : '',
  prefix : ''
 },
 browserPrefixes = 'webkit moz o ms khtml'.split(' ');

 // check for native support
 if (typeof document.cancelFullScreen != 'undefined') {
  fullScreenApi.supportsFullScreen = true;
 } else {
  // check for fullscreen support by vendor prefix
  for (var i = 0, il = browserPrefixes.length; i < il; i++) {
   fullScreenApi.prefix = browserPrefixes[i];

   if (typeof document[fullScreenApi.prefix + 'CancelFullScreen'] != 'undefined') {
    fullScreenApi.supportsFullScreen = true;

    break;
   }
  }
 }

 // update methods to do something useful
 if (fullScreenApi.supportsFullScreen) {
  fullScreenApi.fullScreenEventName = fullScreenApi.prefix + 'fullscreenchange';

  fullScreenApi.isFullScreen = function () {
   switch (this.prefix) {
   case '':
    return document.fullScreen;
   case 'webkit':
    return document.webkitIsFullScreen;
   default:
    return document[this.prefix + 'FullScreen'];
   }
  }
  fullScreenApi.requestFullScreen = function (el) {
   return (this.prefix === '') ? el.requestFullScreen() : el[this.prefix + 'RequestFullScreen']();
  }
  fullScreenApi.cancelFullScreen = function (el) {
   return (this.prefix === '') ? document.cancelFullScreen() : document[this.prefix + 'CancelFullScreen']();
  }
 }

 // jQuery plugin
 if (typeof jQuery != 'undefined') {
  jQuery.fn.requestFullScreen = function () {

   return this.each(function () {
    if (fullScreenApi.supportsFullScreen) {
     fullScreenApi.requestFullScreen(this);
    }
   });
  };
 }

 // export api
 window.fullScreenApi = fullScreenApi;
})();

$(function(){
 $("#fullScreenBtn").click(function(){
  $("#fullScreen").requestFullScreen();
 });

 if(window.top != self){
  $("#tip").text("iframe里面不能演示该功能！请点击右下角的全屏查看！").show();
 }
});

if (!fullScreenApi.supportsFullScreen) {
 alert("您的破浏览器不支持全屏API哦，请换高版本的chrome或者firebox！");