Google calendar CORS error
The browser security model restricts scripts from accessing data delivered from domains other than the one from which the page was loaded, unless the server enables Cross-Origin Resource Sharing (Read the Spec, or a more readable discussion from Adobe).
It appears Google doesn't enable CORS requests on its feeds. From what I'm seeing, you'll have to register as a developer and use the JavaScript API to make Cross-Origin requests: https://developers.google.com/api-client-library/javascript/dev/dev_jscript#Option3UseCORS