Toggle FullScreen onClick

fullscreen.js

if(document.fullscreenElement||document.webkitFullscreenElement||document.mozFullScreenElement||document.msFullscreenElement) { 
		//in fullscreen, so exit it
		alert('exit fullscreen');
		if(document.exitFullscreen) {
			document.exitFullscreen();
		} else if(document.msExitFullscreen) {
			document.msExitFullscreen();
		} else if(document.mozCancelFullScreen) {
			document.mozCancelFullScreen();
		} else if(document.webkitExitFullscreen) {
			document.webkitExitFullscreen();
		}
	} else { //not fullscreen, so enter it
		alert('enter fullscreen');
		if(document.documentElement.requestFullscreen) {
			document.documentElement.requestFullscreen();
		} else if(document.documentElement.webkitRequestFullscreen) {
			document.documentElement.webkitRequestFullscreen();
		} else if(document.documentElement.mozRequestFullScreen) {
			document.documentElement.mozRequestFullScreen();
		} else if(document.documentElement.msRequestFullscreen) {
			document.documentElement.msRequestFullscreen();
		}
	}