jQuery - selecting elements from inside a element

Question

let's say I have a markup like this:

<div id="foo">
  ...
  <span id="moo">
    ...
  </span>
  ...
</div>

and I want to select #moo.

why $('#foo').find('span') works, but $('span', $('#foo')); doesn't ?

Answer 1

Have a look here -- to query a sub-element of an element:

$(document.getElementById('parentid')).find('div#' + divID + ' span.child');