function formatDate(now) { 
                var year=now.getFullYear(); 
                var month=now.getMonth()+1; 
                var date=now.getDate(); 
                var hour=now.getHours(); 
                var minute=now.getMinutes(); 
                var second=now.getSeconds(); 
                return year+"-"+month+"-"+date+" "+hour+":"+minute+":"+second; 
            } 
            
            let nowTime = new Date();
            let time =formatDate(nowTime);
           	$(‘.nowtime‘).text(time)
           	
原文:https://www.cnblogs.com/mmybz/p/8979623.html