Question

I have a hypothetical question, something where by knowledge is a wee bit fuzzy.

If I have a jquery object: Common.$footer = $('.footer');

And I declare it when the footer doesn’t exist, but then the footer gets added later, will the reference work then?

Or a similar scenario if I have did the same when the footer was showing, then it removed, and I used it.

I’m wondering if its ok to setup some references early on in my code, that I can use just later and test if object exists with:

Common.$footer[0] && MyFuncCall();

Also, if I add a element in later on, is it ok to just grab it with $(‘.my-dynmically-added-el’) ? or do I need to use .live or something?

Answer 1

There are no references. Anyway…

$(selector) returns a fixed set of elements that currently match the selector.

If this result is empty then, it will always be empty: the resulting jQuery objects can — and should — be considered immutable, even if the elements they represent can be mutated.

Thus:

x = $('.footer')
// if x.length == 0 then...
// a long time later, assuming x is not assigned to again...
// x.length == 0 is still true

There is live(), but that is different.

Happy coding.