PHP Colour Every Box in the Middle
I have a list of boxes on my website:
box1    box2    box3
box4    box5    box6
box7    box8    box9

Does anybody have a suggestion how to mark every box in the middle of the list (box2, box5, box8)?

Thanks for your help!
PHP Colour Every Box in the Middle
===

I have a list of boxes on my website:
box1    box2    box3
box4    box5    box6
box7    box8    box9

Does anybody have a suggestion how to mark every box in the middle of the list (box2, box5, box8)?

Thanks for your help!