Let's say my source HTML looks like this:
<div id="whatever">...</div>
But my Chrome inspector shows it to me like:
<div id="whatever" class="random-class">...</div>
I can assume that that .random-class was added by a Javascript script, but there are dozens of these scripts on the site. Is there any "standard" way, using the Chrome or FireBug inspector for example, to determine which script is adding this class to my element?