switch(表達(dá)式) {
   case n:
    代碼塊
    break;
   case n:
    代碼塊
    break;
   default:
    默認(rèn)代碼塊
} 

switch (new Date().getDay()) {
  case 0:
    day = "星期天";
    break;
  case 1:
    day = "星期一";
     break;
  case 2:
    day = "星期二";
     break;
  case 3:
    day = "星期三";
     break;
  case 4:
    day = "星期四";
     break;
  case 5:
    day = "星期五";
     break;
  case 6:
    day = "星期六";
}