Convert character to ASCII code in JavaScript

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How can I convert a character to its ASCII code using JavaScript?

For example:

get 10 from "\n".

36 thoughts on “Convert character to ASCII code in JavaScript”

  1. While the other answers are right, I prefer this way:

    function ascii (a) { return a.charCodeAt(0); }

    Then, to use it, simply:

    var lineBreak = ascii("\n");

    I am using this for a small shortcut system:

    $(window).keypress(function(event) {
  if (event.ctrlKey && event.which == ascii("s")) {
    savecontent();
    }
  // ...
  });

    And you can even use it inside map() or other methods:

    var ints = 'ergtrer'.split('').map(ascii);
    Reply

  2. String.prototype.charCodeAt() can convert string characters to ASCII numbers. For example:

    "ABC".charCodeAt(0) // returns 65

    For opposite use String.fromCharCode(10) that convert numbers to equal ASCII character. This function can accept multiple numbers and join all the characters then return the string. Example:

    String.fromCharCode(65,66,67); // returns 'ABC'

    Here is a quick ASCII characters reference:

    {
"31": "",      "32": " ",     "33": "!",     "34": "\"",    "35": "#",    
"36": "$",     "37": "%",     "38": "&",     "39": "'",     "40": "(",    
"41": ")",     "42": "*",     "43": "+",     "44": ",",     "45": "-",    
"46": ".",     "47": "/",     "48": "0",     "49": "1",     "50": "2",    
"51": "3",     "52": "4",     "53": "5",     "54": "6",     "55": "7",    
"56": "8",     "57": "9",     "58": ":",     "59": ";",     "60": "<",    
"61": "=",     "62": ">",     "63": "?",     "64": "@",     "65": "A",    
"66": "B",     "67": "C",     "68": "D",     "69": "E",     "70": "F",    
"71": "G",     "72": "H",     "73": "I",     "74": "J",     "75": "K",    
"76": "L",     "77": "M",     "78": "N",     "79": "O",     "80": "P",    
"81": "Q",     "82": "R",     "83": "S",     "84": "T",     "85": "U",    
"86": "V",     "87": "W",     "88": "X",     "89": "Y",     "90": "Z",    
"91": "[",     "92": "\\",    "93": "]",     "94": "^",     "95": "_",    
"96": "`",     "97": "a",     "98": "b",     "99": "c",     "100": "d",    
"101": "e",    "102": "f",    "103": "g",    "104": "h",    "105": "i",    
"106": "j",    "107": "k",    "108": "l",    "109": "m",    "110": "n",    
"111": "o",    "112": "p",    "113": "q",    "114": "r",    "115": "s",    
"116": "t",    "117": "u",    "118": "v",    "119": "w",    "120": "x",    
"121": "y",    "122": "z",    "123": "{",    "124": "|",    "125": "}",    
"126": "~",    "127": ""
}
    Reply

  4. If you have only one char and not a string, you can use:

    '\n'.charCodeAt();

    omitting the 0…

    It used to be significantly slower than 'n'.charCodeAt(0), but I’ve tested it now and I do not see any difference anymore (executed 10 billions times with and without the 0). Tested for performance only in Chrome and Firefox.

    Reply

  5. For those that want to get a sum of all the ASCII codes for a string:

    'Foobar'
  .split('')
  .map(x=>x.charCodeAt(0))
  .reduce((a,b)=>a+b);

    Or, ES6:

    [...'Foobar']
  .map(char => char.charCodeAt(0))
  .reduce((current, previous) => previous + current)
    Reply

  7. JavaScript stores strings as UTF-16 (double byte) so if you want to ignore the second byte just strip it out with a bitwise & operator on 0000000011111111 (ie 255):

    'a'.charCodeAt(0) & 255 === 97; // because 'a' = 97 0 
'b'.charCodeAt(0) & 255 === 98; // because 'b' = 98 0 
'✓'.charCodeAt(0) & 255 === 19; // because '✓' = 19 39
    Reply

  8. You can enter a character and get Ascii Code Using this Code

    For Example Enter a Character Like A
    You Get Ascii Code 65

    function myFunction(){
    var str=document.getElementById("id1");
    if (str.value=="") {
       str.focus();
       return;
    }
    var a="ASCII Code is == >  ";
document.getElementById("demo").innerHTML =a+str.value.charCodeAt(0);
}
    <p>Check ASCII code</p>

<p>
  Enter any character:  
  <input type="text" id="id1" name="text1" maxLength="1">	</br>
</p>

<button onclick="myFunction()">Get ASCII code</button>

<p id="demo" style="color:red;"></p>
    Reply

  9. To convert a String to a cumulative number:

    const stringToSum = str => [...str||"A"].reduce((a, x) => a += x.codePointAt(0) - 65, 0);

console.log(stringToSum("A")); // 0
console.log(stringToSum("Roko")); // 151

    Use case:

    Say you want to generate different background colors depending on a username:

    const stringToSum = str => [...str||"A"].reduce((a, x) => a += x.codePointAt(0), 0);

const UI_userIcon = user => {
  const hue = (stringToSum(user.name) - 65) % 360; // "A" = hue: 0
  console.log(`Hue: ${hue}`);
  return `<div class="UserIcon" style="background:hsl(${hue}, 80%, 60%)" title="${user.name}">
    <span class="UserIcon-letter">${user.name[0].toUpperCase()}</span>
  </div>`;
};

[
  {name:"A"},
  {name:"Amanda"},
  {name:"amanda"},
  {name:"Anna"},
].forEach(user => {
  document.body.insertAdjacentHTML("beforeend", UI_userIcon(user));
});
    .UserIcon {
  width: 4em;
  height: 4em;
  border-radius: 4em;
  display: inline-flex;
  justify-content: center;
  align-items: center;
}

.UserIcon-letter {
  font: 700 2em/0 sans-serif;
  color: #fff;
}
    Reply

  10. To ensure full Unicode support and reversibility, consider using:

    '\n'.codePointAt(0);

    This will ensure that when testing characters over the UTF-16 limit, you will get their true code point value.

    e.g.

    '𐩕'.codePointAt(0); // 68181
String.fromCodePoint(68181); // '𐩕'

'𐩕'.charCodeAt(0);  // 55298
String.fromCharCode(55298);  // '�'
    Reply 
  11. str.charCodeAt(index)

    Using charCodeAt()
    The following example returns 65, the Unicode value for A.

    'ABC'.charCodeAt(0) // returns 65

    Reply

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