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HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

              <textarea id="stuff">★ counts correctly ★</textarea>
<div id="measure" class="measure">This is <strong><span id="amount">0</span> K</strong> of stuff.<div>
              body {
  text-align: center;
  padding: 1rem;
textarea {
  width: 500px;
  height: 150px;
  margin: 5px;
              $("#stuff").on("keydown blur", function() {
  $("#amount").text(roundNumber(countUtf8($(this).val()) / 1024, 2));

function roundNumber(number, digits) {
  var multiple = Math.pow(10, digits);
  var rndedNum = Math.round(number * multiple) / multiple;
  return rndedNum;

// via https://twitter.com/timcheadle/status/370243309891223552

function fixedCharCodeAt(str, idx) {
    idx = idx || 0;
    var code = str.charCodeAt(idx);
    var hi, low;
    if (0xD800 <= code && code <= 0xDBFF) { // High surrogate (could change last hex to 0xDB7F to treat high private surrogates as single characters)
        hi = code;
        low = str.charCodeAt(idx + 1);
        if (isNaN(low)) {
            throw 'Kein gültiges Schriftzeichen oder Speicherfehler!';
        return ((hi - 0xD800) * 0x400) + (low - 0xDC00) + 0x10000;
    if (0xDC00 <= code && code <= 0xDFFF) { // Low surrogate
        // We return false to allow loops to skip this iteration since should have already handled high surrogate above in the previous iteration
        return false;
        /*hi = str.charCodeAt(idx-1);
        low = code;
        return ((hi - 0xD800) * 0x400) + (low - 0xDC00) + 0x10000;*/
    return code;

function countUtf8(str) {
    var result = 0;
    for (var n = 0; n < str.length; n++) {
        var charCode = fixedCharCodeAt(str, n);
        if (typeof charCode === "number") {
            if (charCode < 128) {
                result = result + 1;
            } else if (charCode < 2048) {
                result = result + 2;
            } else if (charCode < 65536) {
                result = result + 3;
            } else if (charCode < 2097152) {
                result = result + 4;
            } else if (charCode < 67108864) {
                result = result + 5;
            } else {
                result = result + 6;
    return result;
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