What is the difference between ng-click and data-ng-click in angularjs?

Question

From 1st view seems like data-ng-click can pass some data as argument to method should be invoked during pressing on button.

But I don\'t see the differ

Answer 1

Found a difference while using with and without Form.

When my element is in a Form they act the same.

When I use data-ng-click on an element not within a form, Click event is not happening.