Logical sentence part case

Knowledge points

[Web front-end basics | JS basics] Logic statements

Case 1: Printing stars

//打印星星
var str = '';
var n = prompt('请输入打印的星星数的行数：');
var m = prompt('请输入一行要打印的星星数：');
for (var i = 1; i <= n; i++) {
    
    
    for (var j = 1; j <= m; j++) {
    
    
        str = str + '★';
    }
    str = str + '\n';
}
alert(str);

Case 2: Printing Pyramid

//打印金字塔
var str = '';
for (var i = 1; i <= 10; i++) {
    
    
    for (var k = 1; k <= 10 - i + 1; k++) {
    
    
        str = str + ' ';
    
    for (var j = 1; j <= i; j++) {
    
    
        str = str + '★';
    }
    str = str + '\n';
}
alert(str);

Case 3: Printing the nine-nine-nine multiplication table

<script>
    var str = '';
    for (var i = 1; i <= 9; i++) {
    
    
        for (var j = 1; j <= i; j++) {
    
    
            str = str + i + 'x' + j + '=' + (i * j) + '\t';
        }
        str = str + '\n';
    }
    console.log(str);
</script>

Case 4: User login verification

<script>
	//输入正确才可以进行下一步
    var user = prompt('请输入用户名');
    while (user !== 'admin') {
    
    
        user = prompt('请输入用户名');
    }
    var password = prompt('请输入用户密码');
    while (password !== '123456') {
    
    
        password = prompt('请输入用户密码');
    }
    alert('验证通过，我也不知道下一步');
</script>