In HTML there is the "class" attribute like this:
<div class="my_class">Something Something</div>
And you would think that you would retrieve the value of that attribute in C# (which is "my_class") like this:
string x = my_HtmlElement.GetAttribute("class");
But you don't. You need to use:
string x = my_HtmlElement.GetAttribute("classname");
Kind of annoying when you don't know that special name "classname", all the other ones like "href" work as expected, but not "class". I hope I never forget it.
I emailed MSDN about it, seems like it should be on this page.