title: find css classes that have certain styles
body: <p>
  With vanilla js, or with jquery, I want to know all the defined (available) classes that have some styling attribute defined (and what the value is).</p>
  
  <p>For instance, I want to know every class that has the <code>border</code> style defined, and what it is defined to. Being able to modify that class would be great too (i.e. change the border, or delete it), but if push comes to shove, I can just query every element that uses that class and I can switch it over to a class of my choosing instead. </p>
  
  <p>
  I'm trying to write an extension to modify the styling on a popular website. Unfortunately for me, all of the class names are meaningless and the names change frequently (they're all named "class[1..n]") So I can't use class names as a quasi intelligent way to grab certain elements, turn off their old classes and add my new custom ones. The site makes heavy use of inline styles as well and I've been able to get to most of what I need from that. However, there is a class (again, its name changes from "class12" to "class26", etc), that defines a border. I want the border to die. Right now I have to know the content within the border and go up several levels to delete the div with the border class. very annoying.</p>