javascript - 比较 lastName 是否以字母 A-L 开头的 If 语句

Question

我试过运行这段代码，但它不起作用，有人可以帮忙吗？

var lastName = document.queryselector('lastName');
var message = document.queryselector('message');

function checkFirstLetterOfLastName() {
 if (/^[A-L]/.test(lastName)) {
 message.textContent = 'Go stand in first line';
 } else {
 message.textContent = 'Go stand in first line';
 }
}

checkFirstLetterOfLastName();

Answer 1

这是一个使用正则表达式的工作示例:

function checkFirstLetterOfLastName(lastName) {
  if (/^[A-L]/.test(lastName)) {
    console.log(lastName, 'starts with A-L');
  } else {
    console.log(lastName, 'does not start with A-L');
  }
}

checkFirstLetterOfLastName('Carlson');
checkFirstLetterOfLastName('Mathews');