Bitcoin Price Ticker

HTML

<h1>Bitcoin Price Ticker</h1>
<div class="ticker">
  <input type="number" id="btc" value="1" step="any" />
  <input type="text" id="coin" value="BTC" />
  <input type="text" id="currency" value="USD" />
  <p id="price"></p>
  <p id="error" class="error">
</div>

CSS

@import url(https://fonts.googleapis.com/css?family=Pompiere);
body {
  font-family: 'Pompiere', cursive;
  background-color: #E5E5E8;
  margin: 1em;
}

input,
p {
  display: inline;
  font-size: 2em;
  margin-right: 1em;
}

input {
  border-style: none;
  width: 3em;
  text-align: center;
}

input[type=number]::-webkit-outer-spin-button,
input[type=number]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

input[type=number] {
  -moz-appearance: textfield;
}

.ticker {
  padding: 2em;
  margin: 1em;
}

.error {
  color: #e05454;
  display: block;
}

JavaScript

getPrice();
setInterval(function() {
  getPrice();
}, 2000);

function getPrice() {
  var coin = $('#coin').val();
  var currency = $('#currency').val().toUpperCase();
  $.get(`https://cors-anywhere.herokuapp.com/https://www.cryptonator.com/api/ticker/${coin}-${currency}`)
    .done(function(data) {
      if (data.error) {
        $('#price').css('display', 'none');
        $('#error').css('display', 'block');
        $('#error').text('Error !  sure you entered a valid currency code');
      } else {
        if ($('#btc').val() == 1) {
          $('#price').text(`${round(data.ticker.price,2)} ${currency}`);
        } else {
          $('#price').text(`${round(data.ticker.price * $('#btc').val(),2)} ${currency}`);
        }
        $('#error').css('display', 'none');
        $('#price').css('display', 'inline');
      }
    });
}
//From stackoverflow
function round(value, exp) {
  if (typeof exp === 'undefined' || +exp === 0)
    return Math.round(value);

  value = +value;
  exp = +exp;

  if (isNaN(value) || !(typeof exp === 'number' && exp % 1 === 0))
    return NaN;

  // Shift
  value = value.toString().split('e');
  value = Math.round(+(value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp)));

  // Shift back
  value = value.toString().split('e');
  return +(value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp));
}