Question

I have seen the following two variable initializations to create an empty jQuery object. Is there a major difference or advantage to use one over the other?

var a = $({});
var b = $();

Answer 1

If you meant $([]), that’s something from the old days where calling $() was actually equivalent to $(document) (which was an undocumented feature). So to get an empty set, you’d have to call $([]). This was changed in jQuery 1.4; the documented functionality of $() is now to return an empty set.

Passing objects to the jQuery constructor is an entirely different beast. $({}) doesn’t create an empty jQuery object. It creates a jQuery object with a length of 1; the selected item is the object itself.

Passing JS objects to the jQuery constructor lets you take advantage of a more esoteric feature of jQuery: binding and triggering events on (non-DOM) objects.

For example:

var obj = { some: 'stuff' };

$(obj).on('someevent', function() { ... });

$(obj).trigger('someevent');

Either way, if your goal is to instantiate a new, empty jQuery object, use $().