JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-1.12.0.min.js"></script>
 Price (
<label>
  <input type="radio" name="prop_crnt" class="currency" value="0" id="crnt-thb" required>&nbsp;THB</label>
<label>
  <input type="radio" name="prop_crnt" class="currency" value="1" id="crnt-usd">&nbsp;USD</label>):

<input type="text" name="price" class="money" size="15" maxlength="128" placeholder="1,500" required/>

JavaScript

//reset input on radio clicked
$("input[name='prop_crnt']").on('click', function() {
  $('input.money').val('');
  if ($('#crnt-thb').checked) {
    var crncy="฿";
  }else{
  	var crncy="$";
  }
});
//change currency prefix


var format = function(num) {
  var str = num.toString().replace(crncy, ""),
    parts = false,
    output = [],
    i = 1,
    formatted = null;
  if (str.indexOf(".") > 0) {
    parts = str.split(".");
    str = parts[0];
  }
  str = str.split("").reverse();
  for (var j = 0, len = str.length; j < len; j++) {
    if (str[j] != ",") {
      output.push(str[j]);
      if (i % 3 == 0 && j < (len - 1)) {
        output.push(",");
      }
      i++;
    }
  }
  formatted = output.reverse().join("");
  return (crncy + formatted + ((parts) ? "." + parts[1].substr(0, 2) : ""));
};
//currency
$(".money").keyup(function(e) {
  $(this).val(format($(this).val()));
});