When you open your widget locally (like from file://...), the browser blocks AJAX calls to your PHP server due to CORS restrictions and security policies around local files.

To fix this, do :

1. Run your widget through a local server

Instead of double-clicking the HTML file, serve it using a local server. If you have PHP installed, you can do this easily:

php -S localhost:8000

Then open the widget in your browser using:

http://localhost:8000/index.html

Now the browser treats it like a normal web page, and AJAX calls to your PHP server will work (assuming the server allows it).