js转化毫秒为时间格式代码

<script type="text/javascript">
var format = function(time, format){
var t = new Date(time);
var tf = function(i){return (i < 10 ? '0' : '') + i};
return format.replace(/yyyy|MM|dd|HH|mm|ss/g, function(a){
switch(a){
case 'yyyy':
return tf(t.getFullYear());
break;
case 'MM':
return tf(t.getMonth() + 1);
break;
case 'mm':
return tf(t.getMinutes());
break;
case 'dd':
return tf(t.getDate());
break;
case 'HH':
return tf(t.getHours());
break;
case 'ss':
return tf(t.getSeconds());
break;
};
});
};
alert(format(1396178344662, 'yyyy-MM-dd HH:mm:ss'));
</script>