second argument to the $() function

What does second argument of $() function in jquery.

The second argument is context to limit the search

Suppose we have html like below

<ul id="firstList">
	<li>one</li>
	<li>two</li>
	<li>three</li>
</ul>
<ul id="secondList">
	<li>blue</li>
	<li>green</li>
</ul>

if we want to go through the li only under the firstList div we can use $() function’s second argument as below.

$('li','#firstList').each(function(){
console.log($(this).html());
});