XHR Test request in browser console

var data = {a: 1, b: 2};
var xhr = new XMLHttpRequest();
xhr.open('POST', 'https://site.com/send/data', false);
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.send(JSON.stringify(data));
if (xhr.status !== 200) {
    console.log('ERROR');
} else {
    console.log(xhr.responseText);
}