JavaScript generates uppercase and lowercase letters_javascript tips

Mainly use str.charCodeAt() and String.fromCharCode() methods

--》Use charCodeAt() to get the Unicode encoding of a specific character in a string.

--》fromCharCode() accepts one (or more) specified Unicode values ​​and returns the corresponding string.

//生成大写字母 A的Unicode值为65
function generateBig_1(){
  var str = [];
  for(var i=65;i<91;i++){
    str.push(String.fromCharCode(i));
  }
  return str;
}
//生成大写字母 a的Unicode值为97
function generateSmall_1(){
  var str = [];
  for(var i=97;i<123;i++){
    str.push(String.fromCharCode(i));
  }
  return str;
}
//将字符串转换成Unicode码
function toUnicode(str){
  var codes = [];
  for(var i=0;i<str.length;i++){
    codes.push(str.charCodeAt(i));
  }
  return codes;
}

function generateSmall(){
  var ch_small = 'a';
  var str_small = '';
  for(var i=0;i<26;i++){
    str_small += String.fromCharCode(ch_small.charCodeAt(0)+i);
  }
  return str_small;
}

function generateBig(){
  var ch_big = 'A';
  var str_big = '';
  for(var i=0;i<26;i++){
    str_big += String.fromCharCode(ch_big.charCodeAt(0)+i);
  }
  return str_big;
}

console.log(generateBig());
console.log(generateSmall());

console.log(toUnicode(generateBig()));
console.log(toUnicode(generateSmall()));

console.log(generateBig_1());
console.log(generateSmall_1());

Available results--》

Among them, fromCharCode plays a big role in converting html entity symbols