Understanding CORS in AJAX Requests

Learn how to handle Cross-Origin Resource Sharing in your JavaScript code

Photo by Rafael Hoyos Weht on Unsplash

Cross-Origin Resource Sharing (CORS) is a security feature in web browsers. It restricts web pages from making requests to a different domain than the one that served the page. This prevents potentially malicious websites from making unauthorized requests.

In this article, we’ll explain what CORS is and how to handle it when making AJAX requests.

What Is CORS?

CORS is a security mechanism that prevents one domain from making requests to another without permission. When you try to make an AJAX request to a different domain, the browser checks the server’s CORS policy.

If the server allows requests from your domain, the request will proceed. If not, the browser blocks the request to protect the user.

Handling CORS in AJAX Requests

Here’s how you can handle CORS issues when making AJAX requests.

Using the fetch() API

The fetch() API automatically handles CORS for you. Here's how to make a simple GET request with fetch():

const url = 'https://api.example.com/data';

fetch(url)
  .then(response =>…