Question

Given this html:

<ul>
  <li id="1">First</li>
  <li id="2">Second</li>
  <li id="3">Third</li>
</ul>​​​​​​​​​​

And this jQuery:

var $first = $('li').eq(0),
    $second = $('li').eq(1),
    $third = $('li').eq(2);

$second.next($first).css('background-color','red');

Why is the third li element given the background colour of red? I expected that using the cached jQuery object ($first) as a filter would mean nothing would be found.

jsFiddle:

http://jsfiddle.net/Rqw3F/1/

Thanks.

Answer 1

.next only takes a selector string as argument, so your argument is ignored and is effectively the same as:

$second.next().css('background-color','red');

Relevant part from source where non selector string filters are ignored:

    if ( selector && typeof selector === "string" ) {
        ret = jQuery.filter( selector, ret );
    }