html 5フルスクリーン後、keypressまたはkeydownでEscボタンを傍受できません

	//              Esc  
	window.onresize = function(){
		if(!checkFull()){
		//      
			$('#FullScreen').html('  ');
		}
	}

	function checkFull(){
		var isFull =
			document.fullscreenElement ||
			document.mozFullScreenElement ||
			document.webkitFullscreenElement;
	//to fix : false || undefined == undefined
		if(isFull === undefined) isFull = false;
		return isFull;
	}