BlinkStick Pro Kit firefox

Hi People

Looking for some help. Got my blinkstick ordered today and wondering if i can somehow make blinkstick be able to find this line in HTML code of website:
<div class="box-rec br-E1 ">
<div>E1</div>
</div>
and depending on what is “after box-rec-br-” change color ?

Is this even possible ?