How or when the wrap() function is being called

Question

A function is executed only when it's called, how is the wrap function is being called.

Answer 1

The following code

$('span').wrap('div');

would find all span elements and wrap each in a div element, producing the following output:

<div>
<span></span>
</div>

Refer to the documentation at http://api.jquery.com/wrap/.