Where to go for help on boarding to Office 365 development?

I want to get started writing apps for Office 365, but the very first tutorial won't work for me.

Getting Started: https://msdn.microsoft.com/office/office365/howto/getting-started-Office-365-APIs?javascript

I'm sure I've written the code as directed, and I've double checked the instructions.  Nevertheless, when I run my locally hosted one page app in Chrome, I get this error:

XMLHttpRequest cannot load https://outlook.office365.com/api/v1.0/me/messages. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://127.0.0.1:8080' is therefore not allowed access. The response had HTTP status code 400.

Well, adal.js is supposed to take care of that, right?

I sure will appreciate some guidance on this, so, thanks.