postrequest.js

function postRequest(request, endpoint, callback) {
        var xhttp = new XMLHttpRequest();
        xhttp.onreadystatechange = function () {
          if (xhttp.readyState == 4 && xhttp.status == 200) {
            callback(xhttp.responseText);
          }
        };
        xhttp.open("POST", "https://api.traveltimeapp.com/v3/" + endpoint, true);
        xhttp.send(request);
      }