Automatically converts prices to your preferred currency on shopping sites, travel sites, and anywhere prices are displayed.
// ==UserScript==
// @name Auto Currency Converter
// @namespace http://tampermonkey.net/
// @version 1.1
// @description Automatically converts prices to your preferred currency on shopping sites, travel sites, and anywhere prices are displayed.
// @author xvcf
// @match *://*/*
// @grant GM_getValue
// @grant GM_setValue
// @grant GM_xmlhttpRequest
// @license MIT
// ==/UserScript==
(function () {
"use strict";
const config = {
targetCurrency: GM_getValue("targetCurrency", "EUR"),
localCurrency: GM_getValue("localCurrency", "auto"),
updateInterval: 3600000,
maxRetries: 3,
debug: false,
ratesCacheDuration: 3600000,
};
let exchangeRates = {};
let processedElements = new WeakSet();
let isRatesLoaded = false;
function log(message, ...args) {
if (config.debug) {
console.log(`[Currency Converter] ${message}`, ...args);
}
}
const currencySymbols = {
USD: "$",
EUR: "€",
GBP: "£",
JPY: "¥",
CNY: "¥",
KRW: "₩",
INR: "₹",
RUB: "₽",
BRL: "R$",
CAD: "C$",
AUD: "A$",
CHF: "CHF",
};
const pricePatterns = [
/([£$€¥₹₽₩₪₺])\s*([0-9]{1,3}(?:[,.]?[0-9]{3})*(?:[.,][0-9]{1,2})?)/g,
/([0-9]{1,3}(?:[,.]?[0-9]{3})*(?:[.,][0-9]{1,2})?)\s*([A-Z]{3})\b/g,
/\b([A-Z]{3})\s+([0-9]{1,3}(?:[,.]?[0-9]{3})*(?:[.,][0-9]{1,2})?)/g,
/\b([A-Z]{3})([0-9]{1,3}(?:[,.]?[0-9]{3})*(?:[.,][0-9]{1,2})?)/g,
];
function detectCurrencyFromSymbol(symbol) {
const symbolMap = {
$: "USD",
"€": "EUR",
"£": "GBP",
"¥": "JPY",
"₹": "INR",
"₽": "RUB",
"₩": "KRW",
"₪": "ILS",
"₺": "TRY",
};
return symbolMap[symbol] || null;
}
function detectCurrencyFromDomain() {
const domain = window.location.hostname;
const domainMap = {
"amazon.com": "USD",
"amazon.co.uk": "GBP",
"amazon.de": "EUR",
"amazon.fr": "EUR",
"amazon.ca": "CAD",
"amazon.co.jp": "JPY",
"ebay.com": "USD",
"ebay.co.uk": "GBP",
"ebay.de": "EUR",
"booking.com": "EUR",
"airbnb.com": "USD",
"expedia.com": "USD",
"walmart.com": "USD",
"target.com": "USD",
"bestbuy.com": "USD",
"zalando.com": "EUR",
"zara.com": "EUR",
"hm.com": "EUR",
"nike.com": "USD",
"adidas.com": "EUR",
};
for (const [site, currency] of Object.entries(domainMap)) {
if (domain.includes(site)) {
return currency;
}
}
return "USD";
}
function getLocalCurrency() {
if (config.localCurrency === "auto") {
return detectCurrencyFromDomain();
}
return config.localCurrency;
}
async function fetchExchangeRates() {
const cachedRates = GM_getValue("exchangeRates", null);
const cacheTime = GM_getValue("ratesCacheTime", 0);
const now = Date.now();
if (cachedRates && now - cacheTime < config.ratesCacheDuration) {
exchangeRates = JSON.parse(cachedRates);
isRatesLoaded = true;
log("Using cached exchange rates");
return;
}
for (let attempt = 0; attempt < config.maxRetries; attempt++) {
try {
await new Promise((resolve, reject) => {
GM_xmlhttpRequest({
method: "GET",
url: "https://api.exchangerate-api.com/v4/latest/USD",
onload: function (response) {
try {
const data = JSON.parse(response.responseText);
if (data && data.rates) {
exchangeRates = data.rates;
exchangeRates["USD"] = 1;
GM_setValue(
"exchangeRates",
JSON.stringify(exchangeRates)
);
GM_setValue("ratesCacheTime", now);
isRatesLoaded = true;
log("Exchange rates loaded successfully");
resolve();
} else {
reject(
new Error("Invalid response format")
);
}
} catch (e) {
reject(e);
}
},
onerror: function (error) {
reject(error);
},
});
});
return;
} catch (error) {
log(`Attempt ${attempt + 1} failed:`, error);
if (attempt === config.maxRetries - 1) {
const fallbackRates = GM_getValue("exchangeRates", null);
if (fallbackRates) {
exchangeRates = JSON.parse(fallbackRates);
isRatesLoaded = true;
log("Using fallback cached rates");
} else {
log("Failed to load exchange rates");
}
}
await new Promise((resolve) => setTimeout(resolve, 1000));
}
}
}
function parsePrice(priceText) {
const cleanText = priceText.replace(
/[^\d.,£$€¥₹₽₩₪₺₦₵₨₱₸₼₾₮₲₴₪₫₡₧A-Z\s]/g,
""
);
for (const pattern of pricePatterns) {
pattern.lastIndex = 0;
const match = pattern.exec(cleanText);
if (match) {
let amount, currency;
if (
match[1] &&
match[2] &&
!isNaN(parseFloat(match[2].replace(/[,]/g, ""))) &&
/^[£$€¥₹₽₩₪₺₦₵₨₱₸₼₾₮₲₴₫₡₧]$/.test(match[1])
) {
currency = detectCurrencyFromSymbol(match[1]);
amount = parseFloat(match[2].replace(/[,]/g, ""));
} else if (
match[1] &&
match[2] &&
match[2].length === 3 &&
!isNaN(parseFloat(match[1].replace(/[,]/g, "")))
) {
amount = parseFloat(match[1].replace(/[,]/g, ""));
currency = match[2].toUpperCase();
} else if (
match[1] &&
match[2] &&
match[1].length === 3 &&
!isNaN(parseFloat(match[2].replace(/[,]/g, "")))
) {
currency = match[1].toUpperCase();
amount = parseFloat(match[2].replace(/[,]/g, ""));
} else if (
match[1] &&
!match[2] &&
!isNaN(parseFloat(match[1].replace(/[,]/g, "")))
) {
amount = parseFloat(match[1].replace(/[,]/g, ""));
currency = getLocalCurrency();
}
if (
amount &&
currency &&
exchangeRates[currency] &&
amount > 0
) {
return { amount, currency };
}
}
}
return null;
}
function convertCurrency(amount, fromCurrency, toCurrency) {
if (!exchangeRates[fromCurrency] || !exchangeRates[toCurrency]) {
return null;
}
const usdAmount = amount / exchangeRates[fromCurrency];
const convertedAmount = usdAmount * exchangeRates[toCurrency];
return convertedAmount;
}
function formatCurrency(amount, currency) {
const symbol = currencySymbols[currency] || currency;
const formatted = new Intl.NumberFormat("en-US", {
minimumFractionDigits: 2,
maximumFractionDigits: 2,
}).format(amount);
if (symbol.length === 1 && /^[£$€¥₹₽₩₪₺₦₵₨₱₸₼₾₮₲₴₫₡₧]$/.test(symbol)) {
return `${symbol}${formatted}`;
} else {
return `${formatted} ${symbol}`;
}
}
function createConvertedElement(
convertedPrice,
originalPrice,
originalCurrency
) {
const wrapper = document.createElement("span");
wrapper.className = "currency-converter-wrapper";
const converted = document.createElement("span");
converted.className = "currency-converted";
converted.textContent = convertedPrice;
converted.style.cssText = `
font-weight: bold;
color: #e74c3c;
background: linear-gradient(135deg, #ffeaa7 0%, #fab1a0 100%);
padding: 2px 6px;
border-radius: 4px;
font-size: 0.9em;
margin: 0 4px;
display: inline-block;
box-shadow: 0 2px 4px rgba(0,0,0,0.1);
transition: all 0.3s ease;
`;
wrapper.appendChild(converted);
converted.addEventListener("mouseenter", () => {
converted.style.transform = "scale(1.05)";
converted.style.boxShadow = "0 4px 8px rgba(0,0,0,0.2)";
});
converted.addEventListener("mouseleave", () => {
converted.style.transform = "scale(1)";
converted.style.boxShadow = "0 2px 4px rgba(0,0,0,0.1)";
});
return wrapper;
}
function processTextNode(textNode) {
if (processedElements.has(textNode) || !textNode.textContent.trim()) {
return;
}
const parent = textNode.parentNode;
if (!parent) {
return;
}
if (
parent.classList.contains("currency-converter-wrapper") ||
parent.classList.contains("currency-converted") ||
parent.closest(".currency-converter-wrapper")
) {
return;
}
const text = textNode.textContent;
const priceInfo = parsePrice(text);
if (priceInfo) {
if (priceInfo.currency !== config.targetCurrency) {
const convertedAmount = convertCurrency(
priceInfo.amount,
priceInfo.currency,
config.targetCurrency
);
if (convertedAmount) {
const convertedPrice = formatCurrency(
convertedAmount,
config.targetCurrency
);
const convertedElement = createConvertedElement(
convertedPrice,
text,
priceInfo.currency
);
const fragment = document.createDocumentFragment();
fragment.appendChild(convertedElement);
parent.insertBefore(fragment, textNode.nextSibling);
processedElements.add(textNode);
log(
`Converted ${formatCurrency(
priceInfo.amount,
priceInfo.currency
)} to ${convertedPrice}`
);
}
}
}
}
function findAndConvertPrices() {
if (!isRatesLoaded) return;
const walker = document.createTreeWalker(
document.body,
NodeFilter.SHOW_TEXT,
{
acceptNode: function (node) {
if (
node.parentNode.tagName === "SCRIPT" ||
node.parentNode.tagName === "STYLE" ||
node.parentNode.closest(".currency-converter-wrapper")
) {
return NodeFilter.FILTER_REJECT;
}
return NodeFilter.FILTER_ACCEPT;
},
}
);
const textNodes = [];
let node;
while ((node = walker.nextNode())) {
textNodes.push(node);
}
textNodes.forEach(processTextNode);
}
function createToggleButton() {
if (document.getElementById("currency-converter-toggle")) {
return;
}
const button = document.createElement("button");
button.id = "currency-converter-toggle";
button.innerHTML = "💱";
button.title = "Currency Converter Settings";
button.style.cssText = `
position: fixed;
top: 20px;
right: 20px;
width: 50px;
height: 50px;
border-radius: 50%;
background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
border: none;
color: white;
font-size: 20px;
cursor: pointer;
z-index: 2147483646;
box-shadow: 0 4px 12px rgba(0,0,0,0.2);
transition: all 0.3s ease;
`;
button.addEventListener("mouseenter", () => {
button.style.transform = "scale(1.1)";
button.style.boxShadow = "0 6px 16px rgba(0,0,0,0.3)";
});
button.addEventListener("mouseleave", () => {
button.style.transform = "scale(1)";
button.style.boxShadow = "0 4px 12px rgba(0,0,0,0.2)";
});
button.addEventListener("click", () => {
const panel = document.getElementById(
"currency-converter-settings"
);
if (panel) {
panel.style.display =
panel.style.display === "none" ? "block" : "none";
}
});
document.body.appendChild(button);
}
function createSettingsPanel() {
if (document.getElementById("currency-converter-settings")) {
return;
}
const panel = document.createElement("div");
panel.id = "currency-converter-settings";
panel.style.cssText = `
position: fixed;
top: 20px;
right: 20px;
background: white;
border: 1px solid #ddd;
border-radius: 8px;
padding: 15px;
box-shadow: 0 4px 12px rgba(0,0,0,0.15);
z-index: 2147483647;
font-family: Arial, sans-serif;
font-size: 14px;
max-width: 300px;
display: none;
`;
panel.innerHTML = `
<h3 style="margin: 0 0 10px 0; color: #2c3e50;">Currency Converter</h3>
<label style="display: block; margin-bottom: 10px;">
Local Currency (for this site):
<select id="local-currency-select" style="width: 100%; padding: 5px; margin-top: 5px;">
<option value="auto">Auto-detect (${detectCurrencyFromDomain()})</option>
<option value="USD">USD ($)</option>
<option value="EUR">EUR (€)</option>
<option value="GBP">GBP (£)</option>
<option value="JPY">JPY (¥)</option>
<option value="CNY">CNY (¥)</option>
<option value="KRW">KRW (₩)</option>
<option value="INR">INR (₹)</option>
<option value="RUB">RUB (₽)</option>
<option value="BRL">BRL (R$)</option>
<option value="CAD">CAD (C$)</option>
<option value="AUD">AUD (A$)</option>
<option value="CHF">CHF (Fr)</option>
</select>
</label>
<label style="display: block; margin-bottom: 10px;">
Convert To:
<select id="target-currency-select" style="width: 100%; padding: 5px; margin-top: 5px;">
<option value="USD">USD ($)</option>
<option value="EUR">EUR (€)</option>
<option value="GBP">GBP (£)</option>
<option value="JPY">JPY (¥)</option>
<option value="CNY">CNY (¥)</option>
<option value="KRW">KRW (₩)</option>
<option value="INR">INR (₹)</option>
<option value="RUB">RUB (₽)</option>
<option value="BRL">BRL (R$)</option>
<option value="CAD">CAD (C$)</option>
<option value="AUD">AUD (A$)</option>
<option value="CHF">CHF (Fr)</option>
</select>
</label>
<button id="convert-now-btn" style="width: 100%; padding: 8px; background: #3498db; color: white; border: none; border-radius: 4px; cursor: pointer; margin-bottom: 10px;">Save</button>
<button id="close-settings-btn" style="width: 100%; padding: 8px; background: #95a5a6; color: white; border: none; border-radius: 4px; cursor: pointer;">Close</button>
`;
document.body.appendChild(panel);
const localSelect = panel.querySelector("#local-currency-select");
const targetSelect = panel.querySelector("#target-currency-select");
localSelect.value = config.localCurrency;
targetSelect.value = config.targetCurrency;
localSelect.addEventListener("change", (e) => {
config.localCurrency = e.target.value;
GM_setValue("localCurrency", config.localCurrency);
refreshConversions();
});
targetSelect.addEventListener("change", (e) => {
config.targetCurrency = e.target.value;
GM_setValue("targetCurrency", config.targetCurrency);
refreshConversions();
});
panel
.querySelector("#convert-now-btn")
.addEventListener("click", () => {
refreshConversions();
});
panel
.querySelector("#close-settings-btn")
.addEventListener("click", () => {
panel.style.display = "none";
});
return panel;
}
function refreshConversions() {
document
.querySelectorAll(".currency-converter-wrapper")
.forEach((el) => el.remove());
processedElements = new WeakSet();
findAndConvertPrices();
}
async function initialize() {
if (window.currencyConverterInitialized) return;
window.currencyConverterInitialized = true;
await fetchExchangeRates();
if (!isRatesLoaded) return;
createToggleButton();
createSettingsPanel();
findAndConvertPrices();
if (!window.currencyConverterObserver) {
window.currencyConverterObserver = new MutationObserver(() => {
setTimeout(findAndConvertPrices, 1000);
});
window.currencyConverterObserver.observe(document.body, {
childList: true,
subtree: true,
});
}
}
if (document.readyState === "loading") {
document.addEventListener("DOMContentLoaded", initialize);
} else {
initialize();
}
})();