Question

The :last selector is, in some cases, returning more than one element. Here there is a jsfiddle to try it because its hard to believe!

Code one fails:

alert($(".child").find("span:last").length); // -> alerts 3

jQuery documentation:

Description: Selects the last matched element.

Note that :last selects a single element by filtering the current
jQuery collection and matching the last element within it.

Am I missing something or this is a bug?

Answer 1

When you use .find() with :first and :last, it searches for the first and last element relatively to each ancestor element that was found using $('.child').

Since you have three .child elements, you have three elements in which to search for spans. Since each .child has exactly one span, :last turns up each one of those three in the context of .find(). Then .find() collects them all together, and so you have three span elements as a result.