（JavaScript）动态显示日期

window.onload=setInterval(datestr,1000);
function datestr(){ 
  var date = new Date();
var weekday=["星期日","星期一","星期二","星期三","星期四","星期五","星期六"];
  var datestr = "当前日期："+date.getFullYear()+"年"+((Number(date.getMonth()+1)<10 ? ("0"+(date.getMonth()+1)):(date.getMonth()+1)))+"月"+(Number(date.getDate()) <10 ? "0"+date.getDate():date.getDate())+"日　"+weekday[date.getDay()]+" "+((Number(date.getHours()+1)<10?("0"+(date.getHours()+1)):(date.getHours()+1)))+"时"+((Number(date.getMinutes()+1)<10?("0"+(date.getMinutes()+1)):(date.getMinutes()+1)))+"分"+((Number(date.getSeconds()+1)<10?("0"+(date.getSeconds()+1))：(date.getSeconds()+1)))+"秒";
  //方法二：使用switch-case语句
  /*switch(date.getDay()){
    case 0:
      datestr += " 星期日";
      break;
    case 1:
      datestr += " 星期一";
      break;
    case 2:
      datestr += " 星期二";
      break;
    case 3:
      datestr += " 星期三";
      break;
    case 4:
      datestr += " 星期四";
      break;
    case 5:
      datestr += " 星期五";
      break;
    case 6:
      datestr += " 星期六";
      break;
  }*/
  var adv=document.getElementById("dateshow");
  adv.innerHTML=datestr;
  }