does .closest() check itself first?
HTML
.closest() does indeed check itself first.
<div>
<div>
<div>
<div class="baby">
hello
</div>
</div>
</div>
</div>
CSS
div { margin: 5px; padding:5px; border: solid 1px #ccc;}
.bright { border: solid 1px red; }
JavaScript
$(".baby").on("click", function(){
$(this).closest("div").addClass("bright");
});