目录
案例八:设计猜数字小游戏,预定义变量,然后让用户猜变量里面的数字,并提示数字猜大了,猜小了,还是猜对了
案例一:100以内能被3整除的数字和
运行结果:
代码:
<!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>Document</title>
</head>
<body>
<script>
var sum = 0;
var i = 0;
while (i <= 100) {
if (i % 3 == 0) {
sum += i;
}
i++;
}
document.write(sum);
</script>
</body>
</html>
案例二:输出20以内的偶数奇数的个数(包含0)
运行结果:
代码:
<!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>Document</title>
</head>
<body>
<script>
var odd = 0;
var even = 0;
var i = 0;
while (i <= 20) {
if (i % 2 == 0) {
even++;
} else {
odd++;
}
i++;
}
document.write('偶数的个数' + even, '奇数的个数' + odd);
</script>
</body>
</html>
案例三:输入100以内的素数
运行结果:
代码:
<!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>Document</title>
</head>
<body>
<script>
for (i = 2; i <= 100; i++) {
var m = 0;
for (j = 1; j <= i; j++) {
if (i % j == 0) {
m++;
}
}
if (m == 2) {
document.write(i + '<br>');
}
}
</script>
</body>
</html>
案例四:实现1-20数字的平均值
运行结果:
代码:
<!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>Document</title>
</head>
<body>
<script>
var sum = 0;
for (i = 1; i <= 20; i++) {
sum += i;
}
document.write('平均值是' + sum / 20);
</script>
</body>
</html>
案例五:加工零件
运行结果:
代码:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="i-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
// 方法一:
// for (i = 1; i <= 370; i++) {
// if ((i - 10) + (i + 20) + (2 * i) + (i / 2) == 370) {
// document.write('甲的零件数' + (i + 10) + '<br>');
// document.write('乙的零件数' + (i - 20) + '<br>');
// document.write('丙的零件数' + i / 2) + '<br>';
// document.write('丁的零件数' + i * 2) + '<br>';
// }
// }
// 方法二:
for (i = 1; i <= 370; i++) {
// 计算出每一个员工生产的零件个数
var a = i;
var b = i + 30;
var c = (i + 10) / 2;
var d = (i + 10) * 2;
if (a + b + c + d == 370) {
// 通过判断相加之和为370,输出结果
document.write(a + '<br>', b + '<br>', c + '<br>', d + '<br>');
}
}
</script>
</body>
</html>
案例六:鸡兔同笼50只,160脚。求鸡多少,兔多少
运行结果:
代码:
<!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>Document</title>
</head>
<body>
<script>
for (i = 0; i <= 50; i++) {
var j = 50 - i;
if (i + j == 50 && 2 * i + 4 * j == 160) {
document.write(i, j);
}
}
</script>
</body>
</html>
案例七:1000以内的水仙花数
运行结果:
代码:
<!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>Document</title>
</head>
<body>
<script>
for (i = 1; i < 1000; i++) {
var c = parseInt(i % 10);
var b = parseInt(i / 10 % 10);
var a = parseInt(i / 100 % 10);
if (a * a * a + b * b * b + c * c * c === a * 100 + b * 10 + c) {
document.write(i + '<br>');
}
}
</script>
</body>
</html>
案例八:设计猜数字小游戏,预先定义变量值,然后让用户猜变量里面的数字,并提示数字猜大了,猜小了,还是猜对了
运行结果:输入9
代码:
<!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>Document</title>
</head>
<body>
<script>
while (1) {
var num = prompt('猜字小游戏,现在开始,来猜一个数字吧');
focus = 9;
if (num > focus) {
alert('猜大了');
} else if (num < focus) {
alert('猜小了');
} else {
alert('猜对了');
break;
}
}
</script>
</body>
</html>
案例九:编程实现判定一个人是否成年
运行结果:输入18
代码:
<!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>Document</title>
</head>
<body>
<script>
var m = 1;
while (m) {
var age = Number(prompt('请输入您的年龄'));
age >= 18 ? alert('你已成年') : alert('你尚未成年');
var m = prompt('输入1继续\n输入其他退出');
if (m != 1) {
break;
}
}
</script>
</body>
</html>
案例十:编程实现用户输入数字,显示对应的是周几
运行结果:输入2
代码:
<!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>Document</title>
</head>
<body>
<script>
var num = Number(prompt('请输入1-7的数字'));
switch (num) {
case 1:
alert('今天是星期一');
break;
case 2:
alert('今天是星期二');
break;
case 3:
alert('今天是星期三');
break;
case 4:
alert('今天是星期四');
break;
case 5:
alert('今天是星期五');
break;
case 6:
alert('今天是星期六');
break;
case 7:
alert('今天是星期七');
break;
default:
alert('您的输入有误,请重新输入!');
}
</script>
</body>
</html>