A JavaScript question. [more inside]

I’m hoping to copy and paste together a greasemonkey script. I know nothing of JavaScript..

So what I need..

JavaScript that can find all elements with a CSS class. class=“whatever”

I would like to add a CSS style to any <tr> elements that have that class. The end goal is having the row in the table highlighted with a background color when I hover over it.

And I suck at JavaScript..