Why does $('#id') return true if id doesn't exist?

Question

I always wondered why jQuery returns true if I\'m trying to find elements by id selector that doesnt exist in the DOM structure.

Like this:

Answer 1

This behaviour was chosen because otherwise jQuery would regularly throw NullReference Exceptions

Almost all jQuery functions return a jQuery object as a wrapper around the Dom elements in question, so you can use dot notation.

$("#balloon").css({"color":"red"});

Now imagine $("#balloon") returned null. That means that $("#balloon").css({"color":"red"}); would throw an error, rather than silently doing nothing as you would expect.

Hence, you just gotta use .length or .size().