javascript - Jquery selector issue for crawling web pages

Question

When using Jquery to analyze web pages, I feel that both writing methods should be able to choose.
But in fact, the above way of writing is OK, but the following way is not.
The URL is: http://www.shindengen.co.jp/t...

p#newsTab ul.panel dl
p#newsTab ul.panel dl.clearfix

The dl I see in Chrome's F12 developer tool is <dl class="clearfix">
If I look directly at the source code, there is no class attribute. The problem should be here.
But why are the source code and developer tools displayed differently?