Unable to get JSON data from Nominatim's API

My goal is to obtain the longitude, latitude and name of every country and territory in the world, with the help of Nominatim's API, using JavaScript, in order to add them as tiny and clickable points in a Leaflet world map.

Accessing the url using a browser works fine:

https://nominatim.openstreetmap.org/search?country=SG&format=json

It appears that I am unable to receive any of the console.log statements, even with one country:

var XHR = new XMLHttpRequest();
XHR.onreadystatechange = function () {
    if (XHR.readyState == 4 && XHR.status == 200) {
        console.log(XHR.responseText);
    }
};
XHR.open("GET", "https://www.nominatim.openstreetmap.org/search?country=SG&format=json");
XHR.send();
console.log(XHR);

So, I tried a different method, which failed:

let url = 'https://www.nominatim.openstreetmap.org/search?country=SG&format=json';
fetch(url)
    .then(response => response.json())
    .then(function (data) {
        latitude = data.lat;
        longitude = data.lon;
    });
console.log(latitude);
console.log(longtitude);

Please guide me on where I went wrong or what other API I can use to achieve my aforementioned target. Thank you.

Lose the www at the beginning of your URL, nominatim is a subdomain of openstreetmap. This is usually done by the web browser automatically, that's why it doesn't happen when you enter the URL in the browser

Working code:

var XHR = new XMLHttpRequest();
XHR.onreadystatechange = function () {
    if (XHR.readyState == 4 && XHR.status == 200) {
        console.log(XHR.responseText);
    }
};
XHR.open("GET", "https://nominatim.openstreetmap.org/search?country=SG&format=json");
XHR.send();
console.log(XHR);