```javascript
<script>
var money = 100;
do {
var operation = prompt("请输入您要的操作\n 1.存钱 \n 2.取钱 \n 3.显示余额 \n 4.退出");
if (operation === '1') {
var m = prompt("请输入你要存的钱数")
money += parseInt(m)
alert('你的余额为:' + money)
} else if (operation === '2') {
var m = prompt("请输入你要取的钱数")
money -= parseInt(m)
alert('你的余额为:' + money)
} else if (operation === '3') {
alert('你的余额为:' + money)
} else if (operation === '4') {
var flag = confirm('你确定要退出吗')
if (!flag) {
operation = null
}
} else {
alert('请输入正确的操作数字')
}
} while (operation !== '4')
</script>
![img](https://img-mid.csdnimg.cn/release/static/image/mid/ask/724161231436158.png "=600 #left")