$('#id').length may not be a boolean value, but $('#id').length>0 is.
However, in the contexts where you're likely to use this, it doesn't matter:
if( $('#id').length ) ...
or:
$('#id').length ? ... : ...
In either of those cases, the length property works fine for the test,
regardless of whether it's a boolean or a number.
> Well, just to split hairs, the length property returns a number, not a
> true boolean. You could also use:
>
> $('*').is('#myId') or you can reverse it like so: $
> ('#myId').is('*')
>
> The .is() method does return a boolean. An advantage is that you can
> apply this to a subset of elements, for example:
>
> $('a').is('#myId')
> > $('#id').length>0 ?
> > > what is the best way in jquery to check wether an id exists ?
