Question

Html:

<div id="a">
    <span></span>
    <img />
</div>

jQuery:

var a = $("#a").children().find("img"); 

its showing a.length = 0. Whats the problem here?

Answer 1

Use this:

$("#a").find("img");

find searches for descendant of the selectors, and <img> isn’t a descendant of any of <div id="a"> direct childrens.

find docs:

Description: Get the descendants of each element in the current set of matched elements, filtered by a selector, jQuery object, or element.

Live DEMO

Note that you can get the same result with more efficient selector:

$("#a img")...

descendant selector docs:

Description: Selects all elements that are descendants of a given ancestor.

Live DEMO