请问这一段javascript代码为什么一直卡在sum方法无法退到主页面了?求解答
function getNum() {
return parseInt(prompt('请输入一个数值:'));
}
function Solution() {
this.sum = function() {
return getNum() + getNum();
}
this.subtraction = function() {
return getNum() - getNum();
}
this.multiplication = function() {
return getNum() * getNum();
}
this.division = function() {
return getNum() / getNum();
}
}
var v_sn = new Solution();
var num = parseInt(prompt('欢迎使用简易计算器:\n 1.加法运算;\n 2.减法运算;\n 3.乘法运算;\n 4.除法运算;\n 5.退出;\n请输入您的选项:'));
while (true) {
if (num == 5) {
break;
}
switch (num) {
case 1:
alert(v_sn.sum());
break;
case 2:
alert(v_sn.subtraction());
break;
case 3:
alert(v_sn.multiplication());
break;
case 4:
alert(v_sn.division());
break;
default:
alert('没有该选项!');
break;
}
}
假如输入选项1进入加法计算,他就一直卡在加法计算的里面,无法退回到主菜单了,怎么解决?