about id selectors

about id selectors

hi
where can i find an example of how jQuery selects objects when using an id selector?
i'm asking because i've been using a cross browser snippet to select objects and i was wondering if it's the right move to move from the snippet to jQuery.
the snippet checks to see for availabe methods and depending on the one that works, it knows which browser the user is using and selects the object using that method.
i also know jQuery is cross browser, so it's kinda implied, just wanna make sure.