title: Getting index of li which has a class and incrementing
body: <p>I've been all around with hasClass, is(), if then etc. </p>
  
  <p>What I'd like to do is when "btn" is clicked, look through a list of li's, find the one that has the class of "on" and get its index value. Depending on that value, run function x, add the class "on" to the next li and remove the class from the current li.</p>
  
  <p>I want to avoid running comparisons for every index value with a chain of if conditionals</p>
  
  <p>I think I've just been mixing too many selectors and methods. Any code I post here would be even harder to read than possibly that question!</p>
  
  <p>Thanks for those who may get what I'm trying to ask!</p>