app.js

document.addEventListener('DOMContentLoaded', function(){
    document.querySelector('form').onsubmit = function()
    {
            //GET request to URL
            fetch('https://api.exchangeratesapi.io/latest?base=USD')
            .then(response => response.json())
            .then(data => {
                const currency = document.querySelector('#currency').value.toUpperCase();

                const rate =  data.rates[currency];

                if(rate !==undefined) {
                    document.querySelector('#result').innerHTML = `1 USD is equal to ${rate.toFixed(2)} ${currency}`
                } else {
                    document.querySelector('#result').innerHTML = 'Invalid Currency!';
                }

            })
            .catch (error => {
                console.log('Error:', error);
            })

            return false;
    }
})