<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>判断是否是质数</title>
</head>
<body>
<script>
const num = prompt('请输入数字：');
const flag = true;
if (num < 1) {
alert("请输入正确的数字！");
} else if (num == 1) {
alert(num + "不是质数！");
} else {
for (let i = 2; i < num; i++) {
if (num % i == 0) {
flag = false;
break;
}
}
if (flag == true) {
alert(num + '是质数！');
} else {
alert(num + '不是质数！');
}
}
</script>
</body>
</html>
标签：判断,质数,是否是,alert,flag,num,else From： https://www.cnblogs.com/DEYI-L/p/16861527.html