<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>
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>
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
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;
}