currency converter

currency_converter.js

var numberPattern = /\d+/g;
var currencyType = /(GBP)|(PLN)|(USD)|(EUR)/g;

function httpGet(theUrl){
    var xmlHttp = null;
    xmlHttp = new XMLHttpRequest();
    xmlHttp.open( "GET", theUrl, false );
    xmlHttp.send( null );
    return xmlHttp.responseText;
    }
function currencyConverter(currency_from,currency_to,currency_input){
    var yql_base_url = "https://query.yahooapis.com/v1/public/yql";
    var yql_query = 'select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20("'+currency_from+currency_to+'")';
    var yql_query_url = yql_base_url + "?q=" + yql_query + "&format=json&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys";
    var http_response = httpGet(yql_query_url);
    var http_response_json = JSON.parse(http_response);

    return http_response_json.query.results.rate.Rate;
    }
var currency_input = 5;
var currency_to = "PLN";
var usd= currencyConverter("USD",currency_to,currency_input);
var gbp = currencyConverter("GBP",currency_to,currency_input);
var eur = currencyConverter("EUR",currency_to,currency_input);

$('.offer-price').each(function(){
    var getText = $(this).text();
    var value = (parseInt(getText.match( numberPattern ),10));
    var currency = getText.match(currencyType);
    if (currency == "GBP") {
        $(this).text('od '+(Math.round(value*gbp))+' PLN' )
    } else if (currency == "USD") {
        $(this).text('od '+(Math.round(value*usd))+' PLN' )
    } else if (currency == "EUR") {
        $(this).text('od '+(Math.round(value*eur))+' PLN' )
    }
});