JS实现实时显示时间

<p class="col-xs-12 col-sm-6">

 <i class="fa fa-plus-square-o" aria-hidden="true"></i>

 <span id="current-time"></span>
</p>

/*实时显示时间*/

 function showtime(){

 var today,hour,second,minute,year,month,date;

 var strDate ;

 today=new Date();

 var n_day = today.getDay();

 switch (n_day){

 case 0:{

 strDate = "星期日"

 }break;

 case 1:{

 strDate = "星期一"

 }break;

 case 2:{

 strDate ="星期二"

 }break;

 case 3:{

 strDate = "星期三"

 }break;

 case 4:{

 strDate = "星期四"

 }break;

 case 5:{

 strDate = "星期五"

 }break;

 case 6:{

 strDate = "星期六"

 }break;

 case 7:{

 strDate = "星期日"

 }break;

 }

 year = today.getFullYear();

 month = today.getMonth()+1;

 date = today.getDate();

 hour = today.getHours();

 minute =today.getMinutes();

 second = today.getSeconds();

 

 if (month >= 1 && month <= 9) {

 month = "0" + month;

 }

 if (date >= 0 && date <= 9) {

 date = "0" + date;

 }

 if (hour >= 0 && hour <= 9) {

 hour = "0" + hour;

 }

 if (minute >= 0 && minute <= 9) {

 minute = "0" + minute;

 }

 if (second >= 0 && second <= 9) {

 second = "0" + second;

 }

 document.getElementById('current-time').innerHTML ="当前时间："+ year + "年" + month + "月" + date + "日" +" "+ strDate +" " + hour + ":" + minute + ":" + second; //显示时间

 setTimeout("showtime();", 1000); //设定函数自动执行时间为 1000 ms(1 s)

}