设定一个变量标志当前页面是否聚焦，绑定事件调整变量值
要提示信息时，检测是否聚焦，否则设定定时器，频繁变动title

这个闪动频率好像不由得代码控制

		(function(){
			var actived = true;
			var intervaler = null;
			var originTitle = document.title;
			
			window.onfocus = function(){
				actived = true;
				clearInterval(intervaler);
				document.title = originTitle;
				intervaler = null;
			};
			window.onblur = function(){
				actived = false;
				setTimeout(function(){
					showTips('您有新的消息');
				},3000);
			};
			function showTips(tip){
				if(!actived){
					tip = '【'+tip+'】';
					intervaler = setInterval(function(){
						if(document.title === tip){
							document.title = '【      】';
						}else{
							document.title = tip;
						}
					},300);
				}
			}
		})();
		/*
			// IE要用这个
			document.onfocusin = function(){};
			document.onfocusout = function(){};
		*/