JSFiddle - React, Tailwind, and code Playground

by Adem GENC

HTML

<select id="secilen_parabirimi" name="secilen_parabirimi" size="1">
<option value="USD" selected="selected">USD</option>
<option value="EURO" >EURO</option>
<option value="TL" >TL</option>
</select><br /><br /><br /><br /><br /><br />
<input id="fiber_kaynak_ucreti" name="fiber_kaynak_ucreti[]" type="text" value="50.00" /><br />
<input id="kilometre_basi_ucret" name="kilometre_basi_ucret[]" type="text" value="100.00" /><br />
<input id="presonel_basi_ucret" name="presonel_basi_ucret[]" type="text" value="150.00" /><br />
<input id="set_uygulama_ucreti" name="set_uygulama_ucreti[]" type="text" value="200.00" /><br />
<input id="ekstra_uygulama_ucreti" name="ekstra_uygulama_ucreti[]" type="text" value="0.00" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>

JavaScript

$('#secilen_parabirimi').change(function(){
var oldvar = $(this).attr('data-old') !== typeof undefined? $(this).attr('data-old') :"";
var newval = $("option:selected",this).text();
$(this).attr('data-old',newval)

var kilometre_basi_ucret = '100.00'; //$("#kilometre_basi_ucret").val();
var presonel_basi_ucret = '150.00'; //$("#presonel_basi_ucret").val();
var set_uygulama_ucreti = '200.00'; //$("#set_uygulama_ucreti").val();
var ekstra_uygulama_ucreti = '0.00'; //$("#ekstra_uygulama_ucreti").val();
var fiber_kaynak_ucreti = '50.00'; //$("#ekstra_uygulama_ucreti").val();

var secili_para_birimi = 'USD';
//console.log('Eski: ' + oldvar + '\nYeni: ' + newval);
if(oldvar!==undefined){
  $('.secilen_para').text(newval);

const cf = {"USD|TL":"17.9955","EURO|TL":"18.4121","EURO|USD":"1.0232"};

function convert(cf, price, currency_unit, selected_currency)
{
	// if the product currency is the same as the selected currency, return the product price
	if(currency_unit == selected_currency)
	{
		return price;
	}
	// the currency_unit is different, convert the price
	// if the product currency|selected currency matches a from|to entry in cf, multiple by the factor
	var index = currency_unit + '|' + selected_currency;
	if(index in cf)
	{
		return price * cf[index];
	}
	// if the selected currency|product currency matches a from|to entry in cf, divide by the factor
	index = selected_currency + '|' + currency_unit;
	if(index in cf)
	{
		return price / cf[index];
	}
}

    $("#kilometre_basi_ucret").val(convert(cf, kilometre_basi_ucret, secili_para_birimi, newval).toFixed(2));
    $("#presonel_basi_ucret").val(convert(cf, presonel_basi_ucret, secili_para_birimi, newval).toFixed(2));
    $("#set_uygulama_ucreti").val(convert(cf, set_uygulama_ucreti, secili_para_birimi, newval).toFixed(2));
    $("#ekstra_uygulama_ucreti").val(convert(cf, ekstra_uygulama_ucreti, secili_para_birimi, newval).toFixed(2));
    $("#fiber_kaynak_ucreti").val(convert(cf, fiber_kaynak_ucreti,...