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Asked: 2026-06-12T07:45:08+00:00

I am trying to list use the counter in a for loop as the

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I am trying to list use the counter in a for loop as the number of a Unicode character.

To use a Unicode character in JavaScript one can either type it in as it is, or use an escape sequence like: \u8211. My problem arises when I try to combine the number part with the escaped u. The error I get is something along the lines of "bad escape character", and it means that the number from the i variable is not combined with the \u as I’m hoping for.

for (var i=65; i< 90; i++ ) {                                          
    anchor = document.createElement('a'),
    img = document.createElement('img'),
    character = "\\u"+i;
    img.setAttribute('alt', character);
    img.setAttribute('src', '');

    anchor.appendChild(document.createTextNode(i +": "));
    anchor.appendChild(img);

    anchor.setAttribute('title', character);
    body.appendChild(anchor);
    body.appendChild(document.createElement('br'));
}

What I have tried:

character = "\u{"+i+"}"

cha = ['\\u'];
cha.push(i);
cha.join('');

… and I’ve run out of ideas

An example:

body = document.getElementsByTagName('body')[0];

anchor = document.createElement('a');
img = document.createElement('img');
character = "\u8211";

img.setAttribute('alt', character);
img.setAttribute('src', '');
anchor.appendChild(document.createTextNode("x : "));
anchor.appendChild(img);
anchor.setAttribute('title', character);
body.appendChild(anchor);
body.appendChild(document.createElement('br'));


for (var i = 65; i < 87; i++) {
  anchor = document.createElement('a');
  img = document.createElement('img');
  character = "\\u" + i;
  //character = "\u" + i; << bad unicode escape

  img.setAttribute('alt', character);
  img.setAttribute('src', '');
  console.log(img);

  anchor.appendChild(document.createTextNode(i + ": "));
  anchor.appendChild(img);

  anchor.setAttribute('title', character);
  body.appendChild(anchor);
  body.appendChild(document.createElement('br'));
  //console.log( tosay.join(''));
}
body {
  font-size: 12px;
  font-face: monotype;
}
<html>

<head>
  <title>UTF chars</title>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>

<body>
</body>

</html>
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1 Answer

  1. Editorial Team

    The biggest problem is that \uXXXX is interpreted at the time that the code is parsed; just as you can’t write '"' + '"' to mean the same as "" (because " is an actual double-quote in the code, whereas '"' is a string containing "), you can’t write '\\u' + 'XXXX' to mean the same as '\uXXXX'.

    As Brad Christie says in a comment above, you should use the function String.fromCharCode to convert from an integer to the character you need:

    character = String.fromCharCode(i);

    A second problem — this is academic, due to the above, but I think I should mention it — is that the \uXXXX notation expects the character code to be given in hexadecimal notation, and zero-padded to exactly four hexadecimal digits, whereas you’re giving it in decimal notation and without zero-padding. For example, you’re writing \u65, but the Unicode-escape syntax for A is actually \u0041.

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