This is just a quick tip how to find out which version of jQuery is loaded.
It can come in handy for example when you’re developing a script for an existing site and you need to find out which version of jQuery they use. Of course you can always just look in the HTML code, but this method is not always 100% reliable.
$().jquery; // Returns "1.7.1"
jQuery.fn.jquery; // Returns "1.7.1"