A simple, reusable AJAX helper function for GETting JSON

getJson.js

// -----------------------------------------------------------------------------
// SIMPLE REUSABLE AJAX GET JSON FUNCTION
// A frequent thing I find myself writing in projects is a simple function to
// get JSON via AJAX. This simple helper does that in a sensible way without
// needing jQuery or a needlessly complex standalone Ajax library. Get data
// so you can do stuff with it. That’s all it does. No POSTing, no crazy edge-
// case error handling.

function getJson(url, callback) {

  "use strict";

  var request = new XMLHttpRequest();
    
    request.open('GET', url, true);
    
    request.onload = function() {
      if (request.status >= 200 && request.status < 400) {
        var json = JSON.parse(request.responseText);
        
        callback(json);
        
      } else {
        // server error
        console.error("There was an error connecting to the server. The error code was " + request.status);
        return;
      }
    };
    
    request.onerror = function() {
      console.error( "There was an error connecting to the server." );
      return;
    };
    
    request.send();
  
}

// USAGE:
// 
//  getJson("https://randomuser.me/api/", function(data){
//   // Do stuff with the returned data
//  console.log(data.results[0].name.first);
//  });

Great job! It's very helpful. Thank you.