javaScript显示实时时间输出

<script>
function getDateTime(){
		var a = new Date();
		var year = a.getFullYear();
		var mon = a.getMonth() + 1;
		var day = a.getDate();
		var hour = a.getHours();
		var minute = a.getMinutes();
		var second = a.getSeconds();
		var week = a.getDay();
		var arr = ["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];
		document.getElementById("date").innerHTML= year+‘-‘+mon+‘-‘+day+‘ ‘+hour+‘-‘+minute+‘-‘+second+‘<br/>‘+arr[week];
		}

			setInterval("getDateTime()",1000);
</script>


<p id="date"></p>