Detect if a jQuery object is on the page or not

Question

Given a jQuery object, $j, I need to know if it represents something that is already on the page or if it is something that has not yet been put on the page. Fo

Answer 1

With jQuery (at least with version 1.7.1) $('html').parent() returns a non-empty array ([#document]):

$j = $("
I'll cook you some eggs, Margie.
");
$j.parent().length === 0
$('html').parent().length === 1
$('body').parent().length === 1

So 'mu is too short''s note is not an issue:

I can see the first one failing if $j is the html or possibly body; I'm happy to ignore those two pathological cases. I can't think of any way that the second approach would fail.