[jQuery] What does jQuery return for 'null'?

[jQuery] What does jQuery return for 'null'?


Hi, I was just curious as to what jQuery returns instead of 'null'
when it can't find an element?
e.g. if I wanted to run some code if a certain element was on the
page, this doesn't return null:
if ($('#categories') != null) { alert('foo'); }
but getting out of the jQuery object does:
if ($('#categories')[0] != null) { alert('foo'); }
So if it doesn't return 'null', what does it return?