what is wrong in my code?

var room = new XMLHttpRequest();
room.onreadystatechange = function () {
  if(room.readyState === 4 && room.status === 200) {
    var rooms = JSON.parse(room.responseText);
    var statusHTMLr = '<ul class="rooms">';
    for (var i=0; i<rooms.length; i += 1) {
if (rooms[i].available === true) {
      statusHTMLr += '<li class="full">';
      } else {
      statusHTMLr += '<li class="empty">';
      }
    statusHTMLr += rooms[i].room;
      statusHTMLr += '</li>';
    }
  statusHTMLr += '</ul>';
document.getElementById('roomList').innerHTML = statusHTMLr;
  };

};
room.open('GET', '../data/employees.json');
room.send();

          ```