Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript AJAX Basics Programming AJAX Create a callback

Posted by Rebecca Peat
Rebecca Peat
5,292 Points

Parse error when using an arrow function

I've tried this code on the browser console and it works as intended, but the challenge only accepts function declarations.

app.js 
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = () => {

};
xhr.open('GET', 'sidebar.html');
xhr.send();
index.html 
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>AJAX with JavaScript</title>
  <script src="app.js"></script>
</head>
<body>
  <div id="main">
    <h1>AJAX!</h1>
  </div>
  <div id="sidebar"></div>
</body>
</html>
Bert Witzel
.a{fill-rule:evenodd;}techdegree seal-36
Bert Witzel
Full Stack JavaScript Techdegree Graduate 27,918 Points

Sometimes these challenges are looking for something very specific, even though another solution will work, like in your case. XMLHTTPRequest() is kind of outdated anyway, once you learn fetch() you probably won't work with XMLHTTPRequest() again, although it's seen in the wild from time to time.

1 Answer

Steven Parker
Steven Parker
231,261 Points
Steven Parker
Steven Parker
231,261 Points

As Bert points out, this is an older method and it's possible that the course itself is older than the arrow syntax. But you could make a request to the Support folks about updating the evaulator.