JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://raw.github.com/josscrowcroft/accounting.js/master/accounting.min.js"></script>
<select>
    <option value="$">$</option>
    <option value="RUR">RUR</option>
</select>

<input type="text" value="" /> 

<p></p>
<p></p>
<script>
var paragraph_cur = document.getElementsByTagName('p')[0],
    paragraph_num = document.getElementsByTagName('p')[1],
    input = document.getElementsByTagName('input')[0],
    select = document.getElementsByTagName('select')[0],
    
    options_cur_rur = {
        symbol: "RUR",
        precision: 0,
        thousand: " ",
        decima: ",",
        format: {
            pos : "%v %s",
            neg : "(%v) %s",
            zero: "-- %s"
        }
    },
    
    options_num_rur =  {
        precision : 0,
        thousand: " ",
        decimal : ","
    };

var formatIt = function(){
    if (select.value === 'RUR') {
      paragraph_cur.innerHTML = accounting.formatMoney(input.value, options_cur_rur);  
      paragraph_num.innerHTML = accounting.formatNumber(input.value, options_num_rur);       
    } else {
      paragraph_cur.innerHTML = accounting.formatMoney(input.value);  
      paragraph_num.innerHTML = accounting.formatNumber(input.value);           } 

}

select.onchange = input.onkeypress = formatIt;
</script>

JavaScript

var paragraph_cur = document.getElementsByTagName('p')[0],
    paragraph_num = document.getElementsByTagName('p')[1],
    input = document.getElementsByTagName('input')[0],
    select = document.getElementsByTagName('select')[0],
    
    options_cur_rur = {
        symbol: "RUR",
        precision: 0,
        thousand: " ",
        decima: ",",
        format: {
            pos : "%v %s",
            neg : "(%v) %s",
            zero: "-- %s"
        }
    },
    
    options_num_rur =  {
        precision : 0,
        thousand: " ",
        decimal : ","
    };

var formatIt = function(){
    if (select.value === 'RUR') {
      paragraph_cur.innerHTML = accounting.formatMoney(input.value, options_cur_rur);  
      paragraph_num.innerHTML = accounting.formatNumber(input.value, options_num_rur);       
    } else {
      paragraph_cur.innerHTML = accounting.formatMoney(input.value);  
      paragraph_num.innerHTML = accounting.formatNumber(input.value);           } 

}

select.onchange = input.onkeypress = formatIt;