1. let num = 10;
    2. if (num < 11) {
    3. console.log('条件成立执行且退出判断');
    4. } else if (num > 12) {
    5. console.log('条件成立执行且退出判断');
    6. } else if (num == 13) {
    7. console.log('条件成立执行且退出判断');
    8. } else {
    9. console.log('以上条件均不成立时执行');
    10. }