How to use the parsed data in another file?

Question

JSON

varxhr = new XMLHttpRequest();
xhr.open('GET', url, true);
xhr.send();
xhr.onreadystatechange = function() {
if (xhr.readyState != 4) return;
if (xhr.status != 200) {
alert(xhr.status + ': ' + xhr.statusText);
} else {
var eventsList = JSON.parse(xhr.responseText)
}
console.log(eventsList);
}

After parsing, I get an object with data. I can extract everything I need from it, but only within the function. How to redefine variables so that they can be used in other files (or just outside the scope of this function)? I'm completely confused .. Help, please !!
Thank you!