我正在尝试改变字符串中英文字母的顺序，使a的字母顺序为z，b的字母顺序为y，依此类推。反之亦然

function reverseString(str) {
  var charArray = str.split('');
  
  for (var i = 0; i < charArray.length; i++) {
    var char = charArray[i];
    
    if (char >= 'a' && char <= 'z') {
      charArray[i] = String.fromCharCode('z'.charCodeAt(0) - (char.charCodeAt(0) - 'a'.charCodeAt(0)));
    } else if (char >= 'A' && char <= 'Z') {
      charArray[i] = String.fromCharCode('Z'.charCodeAt(0) - (char.charCodeAt(0) - 'A'.charCodeAt(0)));
    }
  }
  
  return charArray.join('');
}

var originalString = "Hello World!";
var reversedString = reverseString(originalString);
console.log(reversedString);  // 输出 "Svool Dliow!"