Question

What does the ‘function’ do in the following?

$('.event-row').on('mouseover',function(){
  arc.event_handler.event_row_over();
  });

$('.event-row').on('mouseover',arc.event_handler.event_row_over );

Answer 1

There’s a very important difference.

• The first one will call the function with the context its this value as the event_handler object.

• The second one will call the function with the context its this value as the DOM element to which the handler is bound.

So the first one preserves the expected calling context this value, which may be required by the function.