急死了，帮帮忙啊~~

Question

 <script language="JavaScript">
   var num=window.prompt("请输入数字","");
   switch(num){
           case 0:alert("Sunday");
            break;
           case 1:alert("Monday"); 
           break;
           case 2:alert("Tuesday");
              break;
           case 3:alert("Wednesday");
            break;
           case 4:alert("Thursday");
           break;
           case 5:alert("Friday");
             break;
           case 6:alert("Saturday");
            break;
           }
</script>

Answer 1

case "0"
case "1"
case "2"
case "3"
...
加上引号，因为你得到的是字符串，不是数字，
或者用parseInt转换成数字

Answer 2

var num=window.prompt("请输入数字","");
switch(num){
case "0":alert("Sunday");
break;
case "1":alert("Monday"); 
break;
case "2":alert("Tuesday");
break;
case "3":alert("Wednesday");
break;
case "4":alert("Thursday");
break;
case "5":alert("Friday");
break;
case "6":alert("Saturday");
break;
}