How to convert a char to its keycode?

Question

How can I convert a character to its respective keycode?

For example:

• a to 65
• b to 66
• c to 67
• d to 68

Answer 1

You can use the charCodeAt function to achieve this.

Working example:

function showKeyCode () {
    var character = document.getElementById("character").value.substring(0, 1);
    var code = document.getElementById("character").value.charCodeAt(0);
    var msg = "The Key Code for the \"" + character + "\" character is " + code + ".";
    alert(msg);
}

<input type="text" id="character" size="15">
<input type="button" value="Show Key Code" onclick="showKeyCode();">

Answer 2

What do you mean by "keyCode"? Different browsers have different keyCode values in keyup and keydown events which will not necessarily correspond to the ASCII code for the corresponding character. For alphanumeric keys, the keypress event will give you the ASCII code in most browsers via the charCode or which properties. This page is useful.

Update September 2015

As pointed out by Jan in the comments, keyCode will eventually be superseded by the superior key property. However, there is not much browser support for this yet.

Answer 3

Here is a object with some keys and their corresponding keycodes:

{"0":48,"1":49,"2":50,"3":51,"4":52,"5":53,"6":54,"7":55,"8":56,"9":57,"d":68,"b":66,"a":65,"s":83,"i":73,"f":70,"k":75,"ß":219,"Dead":220,"+":187,"ü":186,"p":80,"o":79,"u":85,"z":90,"t":84,"r":82,"e":69,"w":87,"g":71,"h":72,"j":74,"l":76,"ö":192,"ä":222,"#":191,"y":89,"x":88,"c":67,"v":86,"n":78,"m":77,",":188,".":190,"-":189,"ArrowRight":39,"ArrowLeft":37,"ArrowUp":38,"ArrowDown":40,"PageDown":34,"Clear":12,"Home":36,"PageUp":33,"End":35,"Delete":46,"Insert":45,"Control":17,"AltGraph":18,"Meta":92,"Alt":18,"Shift":16,"CapsLock":20,"Tab":9,"Escape":27,"F1":112,"F2":113,";":188,":":190,"_":189,"'":191,"*":187,"Q":81,"W":87,"E":69,"R":82,"T":84,"Z":90,"S":83,"A":65,"D":68,"I":73,"U":85,"O":79,"Y":89,"X":88,"C":67,"F":70,"V":86,"G":71,"B":66,"H":72,"N":78,"J":74,"M":77,"K":75,"L":76,"P":80,"Ö":192,"Ä":222,"Ü":186,"!":49,"\"":50,"§":51,"$":52,"%":53,"&":54,"/":55,"(":56,")":57,"=":48,"?":219,"°":220}

if some keys are missing or are different for your browser, you can use the following function:

let a = {}
document.addEventListener("keydown", ({key, keyCode}) => a[key] = keyCode);

Just copy it to the console and smash your head on the keyboard. The result will be stored in a

Answer 4

As pointed out in the comments: the accepted answer is not correct, because it gives the character code and not the keyCode, which can be different, e.g. 'a'.charCodeAt(0) == 97 while the correct keyCode is 65.

for converting just the standard characters from [a-zA-Z] or numbers [0-9] the code below can be used.

However this does not work correctly for any special keys like ., Ö, # or whatsoever and I did not find a good solution for them. As a workaround one could use a site like http://keycode.info/ (which just captures the onkeydown events and reads the event.keyCode property).

function convertToKeyCode(target) {
    var keyCode = target.value.toUpperCase().charCodeAt(0);
    document.getElementById("keyCodeSpan").innerHTML = keyCode;
}

<input type="text" oninput="convertToKeyCode(this)" size="1" maxlength="1">
<span>Keycode: </span><span id="keyCodeSpan"></span>

Answer 5

Find a keycode/ascii chart like this one and put it into an array such that array['char'] = keycode. This is tedious, but the code will execute pretty fast.

Answer 6

I was searching for this when I stumbled upon this question. I do not think the marked answer is the right answer. For simple letters, A-Za-z, I use the following:

function getKeyCode(char) {
  var keyCode = char.charCodeAt(0);
  if(keyCode > 90) {  // 90 is keyCode for 'z'
    return keyCode - 32;
  }
  return keyCode;
}

Please note that this is meant to work for characters A-Z and a-z only.

Answer 7

let character = prompt('input a character');

console.log(character.charCodeAt(0));

for basic concept,you should use the method 'string.charCodeAt(0)'. for Example in Javascript , 'A'.charCodeAt(0).