AJAX request for JSON file (local) - Array

app.js

var btn2 = document.getElementById('button2');

btn2.addEventListener('click', loadUsers);

//REQUEST ALL USERS DATA
function loadUsers(){
    var xhr = new XMLHttpRequest();
    xhr.open('GET', 'assets/json/users.json', true);

    xhr.onload = function(){
        if(this.status = 200){
            var users = JSON.parse(this.responseText);

            var output = '';

            for(var i in users){

                output += '<ul>' +
                    '<li>ID: '+ users[i].id +'</li>' +
                    '<li>Name: '+ users[i].name +'</li>' +
                    '<li>Email: '+ users[i].email +'</li>' +
                    '</ul>';
            }

            document.getElementById('users').innerHTML = output;
        }
    }

    xhr.send();
}