How to return data to my app with JavaScript or AngularJS?

I am still learning this framework and I don’t understand how return data to my app with JavaScript. Help me please !

There is an example here:

https://backendless.com/feature-16-data-retrieval-api-how-to-load-objects-from-an-mbaas-storage/

And the doc is here: https://backendless.com/documentation/data/js/data_basic_search.htm

Regards,
Mark

Thank’s so much !!!