倒计时关闭页面

 <script>
            var otimer;
			var second=60;
			function timer(){
			otimer.innerHTML=second;
			if(second>0){
					second=second-1;
					return false;
			}
				window.close();
			}
			window.onload=function(){
				otimer=document.getElementById('timer');
				setInterval(timer,1000)
			}
			</script>
			<div id="timer"></div>