CSS selector with class a but not class b

Question

I've tried all sorts of things but I think i'm getting too complicated and even managed to get chrome to hang with my selector. I'm sure theres a simple way to do this

Select classa but only when theres no classb and ignore the last instance of it

<div class="container">     <div class="classa classb"></div> <!-- Dont Select -->     <div class="classa"></div>  <!-- Select -->     <div class="classa"></div>  <!-- Dont select last instance --> </div> 

Answer 1

I believe you can do this with CSS3 using the :not() selected (example here)

div.classa:not(.classb):not(:last-child) {}

However, as you know, not many browser supports this, so Javascript might be an easier way...