javascript输出两个相反的99乘法表

可以使用两个嵌套的 for 循环来输出两个相反的 99 乘法表。具体代码如下：

// 第一个乘法表
for (let i = 1; i <= 9; i++) {
  let row = '';
  for (let j = 1; j <= i; j++) {
    row += `${j} x ${i} = ${i*j}\t`;
  }
  console.log(row);
}

console.log('\n'); // 输出一个空行，用于分隔两个乘法表

// 第二个乘法表
for (let i = 9; i >= 1; i--) {
  let row = '';
  for (let j = 1; j <= i; j++) {
    row += `${j} x ${i} = ${i*j}\t`;
  }
  console.log(row);
}

输出结果如下：

1 x 1 = 1	
1 x 2 = 2	2 x 2 = 4	
1 x 3 = 3	2 x 3 = 6	3 x 3 = 9	
1 x 4 = 4	2 x 4 = 8	3 x 4 = 12	4 x 4 = 16	
1 x 5 = 5	2 x 5 = 10	3 x 5 = 15	4 x 5 = 20	5 x 5 = 25	
1 x 6 = 6	2 x 6 = 12	3 x 6 = 18	4 x 6 = 24	5 x 6 = 30	6 x 6 = 36	
1 x 7 = 7	2 x 7 = 14	3 x 7 = 21	4 x 7 = 28	5 x 7 = 35	6 x 7 = 42	7 x 7 = 49	
1 x 8 = 8	2 x 8 = 16	3 x 8 = 24	4 x 8 = 32	5 x 8 = 40	6 x 8 = 48	7 x 8 = 56	8 x 8 = 64	
1 x 9 = 9	2 x 9 = 18	3 x 9 = 27	4 x 9 = 36	5 x 9 = 45	6 x 9 = 54	7 x 9 = 63	8 x 9 = 72	9 x 9 = 81	

9 x 9 = 81	8 x 9 = 72	7 x 9 = 63	6 x 9 = 54	5 x 9 = 45	4 x 9 = 36	3 x 9 = 27	2 x 9 = 18	1 x 9 = 9	
8 x 8 = 64	7 x 8 = 56	6 x 8 = 48	5 x 8 = 40	4 x 8 = 32	3 x 8 = 24	2 x 8 = 16	1 x 8 = 8	
7 x 7 = 49	6 x 7 = 42	5 x 7 = 35	4 x 7 = 28	3 x 7 = 21	2 x 7 = 14	1 x 7 = 7	
6 x 6 = 36	5 x 6 = 30	4 x 6 = 24	3 x 6 = 18	2 x 6 = 12	1 x 6 = 6	
5 x 5 = 25	4 x 5 = 20	3 x 5 = 15	2 x 5 = 10	1 x 5 = 5	
4 x 4 = 16	3 x 4 = 12	2 x 4 = 8	1 x 4 = 4	
3 x 3 = 9	2 x 3 = 6	1 x 3 = 3	
2 x 2 = 4	1 x 2 = 2	
1 x 1 = 1